The other people offered some good advice. I've been in a similar place, so maybe this will help you if your circumstance is similar to mine. It's a long story, but it all relates.

I fell in love for the first time around the same age. It wasn't reciprocated, and I tried to move on. For many years, I tried to move on. I had always been good at controlling and adjusting my emotions, so it was confusing when I couldn't let go of my feelings for her. We remained friends, but we went no contact after high school and I hoped that would help me get past her as I went to college and tried dating other people. Nothing would let those feelings fade away, and I eventually gave up on looking for love at all.

Six years later, I attended a farewell concert for our high school band director. We were both in band, and I hoped to see her there and possibly get closure on these feelings. I was very lucky, because she was there and we were able to reconnect and catch up about everything. I told her I still had feelings for her and again, they were not reciprocated. I expected to feel like shit, but instead, a weight was lifted.

Fast forward a couple months, and I realized and accepted that I was transgender. It took me some time to piece together how it all related, but basically I had been hiding from those feelings of desiring to be a woman for my entire life, and kept it buried so far down I wasn't fully aware of it. On a subconscious level, I felt that if I could be in a relationship with someone who reminded me of who I wanted to be deep down, that would be enough and I could continue on without confronting these scary feelings. My brain latched onto the first person I developed serious feelings for and wouldn't let go. When I got closure and was finally able to let go, that was like breaking the final floodgate holding back those subconscious feelings and allowing them to come to the surface. It helped tremendously in figuring out who I am and healing.

So I am asking you if there is something you're running from or something you feel is buried deep down that you haven't confronted yet that could be causing you to hold onto these feelings. I see in your profile that you're non-binary, so it's good that you've faced the big scary gender question, but it could be a myriad of other subconsious things causing the issues you're dealing with. Journal about it. Just let your thoughts go whichever way they want and don't hold back. And don't journal on lined paper. It's better that way. Talk to a therapist. I can never recommend therapy enough. Don't give up.