This is such a good question, and I am so glad that you had the courage to ask it. I think many people feel this way at times, but cannot always articulate what is happening for them in the moment. It can feel sometimes as though you are just going around and around in your thoughts, and end up utterly paralyzed by what feels like the weight of the world.
I'm going to just briefly mention a 'quick fix' which actually can work sometimes, and then I'll explain a bit more about an approach that can be helpful in the longer-term.
"The Quick Fix"
One of the most difficult things to do is to stop overthinking everything, especially when you have ADHD. Taking those first steps to perform any action that is 'outside of one's own thought processes' is not at all easy. So, in this quick-fix, you might recognize how easy it is for it not to work, and how easy it is to simply fall back into into a cycle that keeps you stuck in that one place.
With this technique, you are doing your best to draw your immediate focus away from what you are feeling and thinking.
Find the target, and go for it. No thinking about what it means, how hard it will be, what it will cost, what could happen next, how it's going to feel, and so on.
Push down on the bed with your arms and hands as much as you can, look at the door (as a target to get to) push yourself up (as though you were helping someone else to move), keep your eyes on the target, drag yourself towards it, grab the handle, pull the door open and push yourself into the next area.
This may sound a little strange, but sometimes, depending on what is going on inside of you at the time, it can actually do the trick. Right there and then, in that specific moment. Rather like escaping from the binds that were holding you in place. I like to think of this as a "stop 'n go" technique and I would love to hear about how you get on, if you do manage to try this.
Starting on the longer (but more sustaining) path:
A longer-term approach is more complex but well-worth the effort. I'll do my best here to explain how you can get started, and I would always advise you get some help, from anyone, to help to manage the difficult feelings along the way. This could be a professional, or just someone who cares about you in everyday life - anyone who you can take a moment with just to say 'I feel like crap and it's okay'.
Learning to Negotiate with Yourself
A helpful way could be to start learning to 'negotiate with yourself'. I don't mean going through mental lists of what you think you got wrong in life, mistakes you've made, observing yourself from the outside with a judgmental attitude. What I mean is just having a discussion with yourself, trying to take an objective, reasonable perspective and taking a look at the bigger picture in an honest and direct way.
So, how would you normally solve a problem? The first step would usually be noticing that there is a problem. It seems basic, but identifying that 'something's up, can help put you into a more helpful state of mind.
Right now, you may not be able to say what the problem is, identify it clearly, name it, and so on - but that's okay. We're at step 1.
Step 2 is to double check on what you actually 'know' to be true, and try to separate that from what you 'feel' might be true. This will help you to be less judgmental of yourself - we are not making any decisions or coming to any conclusions about anything - all we truly know (and can prove) is that there's something causing a problem and we're acknowledging it.
Having acknowledge the existence of 'a problem', we can do a number of things. Asking for help if you can - asking others for ideas, thoughts, feelings, engaging in some level of exploration. Again, no judgements are being made, because we are just at the exploration stage.
If asking for input from anyone else is not possible or may not be something you think is helpful - the next step is to consider asking someone who 'might' know something. That person is of course, you. It isn't clear, it isn't obvious, but at least you know that somewhere, within the vaults of your own mind, there are some pieces of the puzzle - and that at some point, you will have more information, which can help to give you a clearer picture.
At this point, you don't want to be drawn into another argument with yourself or being swept away down another train of thought leading to the same places as before. So you pull yourself back to the beginning and look at the main points that you can prove to be true.
a. There is a problem
b. If I do the usual thing, I won't get the outcome I want.
c. I know that somewhere in me, there are bits of information that can help.
So, we now have more 'true' information than we did before.
Time to breathe and think about it. Try to give your brain and body time to process all this.
Continue the negotiation process ...
When you have done a little breathing and are feeling a little more settled, you can continue the process by summarizing the thoughts into brief points (as we did above) and reiterating them to yourself. Acknowledging what you know (and can prove) to be true.
The next step is to keep an eye on your breathing, and keep trying to draw your focus back to the process - remind yourself why you are doing this, and again, reiterate the summary. If you do manage to pull your focus back to the process, even just for a moment, then it is time to take the next, and most important step so far.
What you will have achieved in this exercise, is to exert control over your own body and mind - even if it was just for a few moments.
You changed something.
You actually did do something that was not easy. The easy thing to do would have been to just 'go with the flow that I know!' But you didn't. You actually changed something that you've been fighting and struggling with, you took charge of something, in that moment, and you redirected the flow - even if only for a few seconds.
You will now have achieved something meaningful. The reason you need to stop and really acknowledge your progress, is because you are giving yourself a little bit of 'positive reinforcement'. By doing this, you are helping your rational brain and also your emotional and psychological brain, to be able to recognize that you are doing something helpful. You are not trying to deceive yourself - you are just acknowledging that which is true.
With more and more practice, your brain can start to recognize you as a 'powerful actor' rather than attempting to keep you in one place. You start to learn to trust yourself a little more, not being too afraid of getting things wrong, making mistakes, and learning to think about things in a way that is 'true'. YOU did something, rather than something being done TO you. Acknowledge, summarize, and reinforce.
By doing all of these things, you are starting to negotiate with yourself in an honest and direct way. You are acknowledging the good things equally and giving yourself some credit for when you've actually achieved something helpful. When this happens, you are essentially giving yourself time and space to store some genuine 'good' feedback. This gives you energy that you can hold onto for later on, to help you feel more able to manage more complex challenges.
This could be enough for one day, and I would suggest trying this as best as you can and as often as you can.
Final Note ...
In those moments, when you become frustrated with yourself, and you pass judgement on yourself in a negative way - try to remind yourself about what you actually KNOW, instead of what you FEEL. Ask yourself, "Would I pass judgement upon someone else, with so little provable information?"
It might be time to give yourself the benefit of the doubt and start to give yourself a chance, as you would give anyone else a chance to figure things out.
The best that you can do right now, is to treat yourself like someone you care about. Even when it feels weird - give yourself the same kindness, compassion, and time - to get where you need to be, to be able to get a handle on things and make helpful steps forward. Like a baby learns to take those first wobbly steps - in time, learns to walk more confidently, and then to run, ... and then can reach the door handle and charge though the door - feeling empowered and ready to deal with whatever challenges lay ahead.