How do I stop these feelings I have for someone? Regretful over not pursuing them?

Having feelings for someone can impact people differently. We may be really attracted to someone, or we may be so drawn to them that it can feel impossible to function without them as our partner. There are different reasons why relationships may not be pursued with the other person, which can include feelings not reciprocated or not feeling ready to be in a relationship. Exploring these reasons further can help us better understand ourselves and why we respond the way that we do.

It sounds like you mentioned that you two did reciprocate feelings for each other at some point. And it sounds like in your mind, you made the decision that it would not work. What led you to feel this way? Sometimes lifestyle choices or personality styles can cause us to question if it would be a good fit. Other times, we may be self-sabotaging as we may not feel like we are good enough for the other person. Either way, it sounds like you made a prediction that you didn't think that it would work. And now, did that change or do you know feel it can work? It is important to really think about what led to the change of thought. Or is this more of a curiosity of what could have been if you two had gotten together? Being curious about a relationship that didn't take place is a very normal thing to happen especially if other relationships didn't work out. Sometimes we may consider what could have happened and what if things had gone well. But in reality, we may never know how things would have gone.

Many times we don't consider how the timing can be a big factor in whether we pursue a relationship. For instance, we may have recently broken up from a relationship and may still be grieving the loss of the relationship. And if so, it is important that we give ourselves time to heal before we move on. Sometimes we may not feel worthy or like we are ready to get into a relationship if our self-esteem isn't at it's highest point. It is important that we do some self-exploration as to what makes us believe the relationship didn't work or couldn't work for us? 

You also mentioned how anxiety may be a reason why you may not have pursued this relationship in the past. And sometimes worrying about the outcome or the possibility of the relationship may lead to stressful feelings or thoughts that may get in the way of pursuing relationships or exploring what they could be. Pursuing any relationship has risk as we don't know if it will work out or if it won't. Many times, this can lead us to hold back if we don't feel sure if it's worth taking the risk. And this can go back to timing. If we are not in the correct head space to take on a relationship, it may not be the best time for us to pursue it at that time.

So you do have a couple of options. As you mentioned you can attempt to move on, but wondering if you have considered communicating with this person how you feel about them? If this person felt the same, is there a possibility that the relationship could be pursued now? If this doesn't feel like it's an option (as they may be committed to someone else or not in a place to start a relationship now), then of course you may want to consider moving on or pursuing other dating options.

One thing that I would also consider is to forgive yourself for not pursuing the relationship when you did. Anxiety can get the best of us, and we may not be ready to explore certain things in our lives. And learning to forgive ourselves for not being ready may be helpful. It is a process, but can be quite helpful in reminding yourself that it may not have been the best time to explore that relationship back then. And if that's the case, do you feel like you got a better grasp on your anxiety today? Depending on that answer, you may now feel ready to pursue a relationship with someone and that's great. It may just not be with the person that you envisioned. But that doesn't mean that's a bad thing either. 

In terms of this person that you are attracted to, what do you like about them? I would definitely make note of those qualities and continue to search for those and other qualities that you like in future people that you will date. Dating new people can help you explore options with people who also want to meet new people or are in a place to explore a potential relationship. But this option is something to really think about when you are ready to meet new people. Sometimes even processing that things didn't work out or can't work out with someone takes some time. I would definitely consider giving yourself some time to process.

In terms of managing anxiety and navigating relationships/dating, this can take some time for people to figure out. There are some great self-help books that can provide some techniques to reduce anxiety and also figure out what you are looking for in a partner. However, if you need more support or guidance, I would consider seeking mental health counseling services from a therapist. You can then further explore some of these themes with a professional. Best of luck with everything on your journey of self-exploration.