I fell in love and now she's moved on

Thank you for reaching out and seeking guidance.  I am so sorry you're going through such a painful time.  Knowing someone for so long with 8+ years of being romantic, is a VERY long time in general...then when you throw in cutting off no contact, whoa, I can only imagine how hard that is!  When you have so much history with someone like that, it makes a ton of sense as to why you're having a difficult time moving on.  And no matter the type of relationship you had, when we are a part of something for so long, we become comfortable.  That's why a lot of the time, even if we know we want to/or need to make a change, we don't because the familiar is just that, familiar.  While my feedback will solely be based on the information included in your inquiry, please keep in mind that working with a therapist in real time where you can unpack more of the specifics can be a very helpful tool for you as you learn to navigate your world post-relationship.

With that being said, the first thing I want to acknowledge is that how you're feeling right now is absolutely normal and part of your grieving process.  What have you done so far to "get her out of your head", as you put it?  And has anything worked, even if just for a little bit?  Sometimes being able to distract ourselves so we aren't alone with our thoughts is a good way to do something we enjoy as well as fill our minds with things other than the pain we're experiencing.  You may be thinking that distractions can only go so far and that is correct...however I do believe there is a time and place for them. 

Equally as important to finding distractions is looking at your thought patterns and your internal dialogue to see if there is something that we can change.  What are some things that you think about when you can't get her out of your mind?  A good exercise could be to write down these thoughts so you can see them and actively dispute them.  I personally like the visualization of the angel on one shoulder and the devil on the other and you're talking the devil down proverbially speaking.  This technique is called challenging negative thoughts and it allows us to look at the content of what we're thinking and if there is any validity to those thoughts.  It sounds like she didn't treat you well and this could be a good reminder that you deserve more than what she was able to give.  Another thing to think about is if you have a support system or in the very least, someone with whom you can confide?  This can be a very lonely time and being able to have someone to talk to could be gamechanging.  

Everyone experiences feelings of loss differently.  I am a firm believer that people come into our lives at various points for a reason - even if we don't exactly understand it at that time - and sometimes relationships just run its course.  I mention that not to diminish your relationship with her, but to start thinking about the meaning of that relationship in a little bit of a different way.  I hope that you are able to connect with a therapist so you can continue unpacking everything that you're going through and I would like to end with this thought - instead of looking at it as how do I move on, what happens if you look at it as how do I move forward?