How to move on?

Okay so I'll try to make this as short as possible: I dated a guy long distance from Febuary-June of last year. He was my first love, first kiss- basically first everything- and vice versa for him. I was head over heels for him, and we broke up because of some problems caused by the distance. I met him when I was 16 and I'm 17 now. He lives 2 hours away, but I see him every few months because I have family near where he lives. I was DEVASTATED when we broke up- cried every night for about 3 months and continued to feel absolutely awful until October when we began to talk again. We quickly became best friends again and went back to facetiming every night and texting constantly. We basically act like we're dating. I saw him this weekend for the first time since June and something just seemed a bit off and it's throwing me off completely. I still love him so much- we kissed, cuddled, and had sex for the first time. Something tells me that I'm acting stupid and that it's been a year of me being hung up on him, but no matter what I do I can't move on to any other guys (I've tried). The level of comfort I've reached with him is something that I never want to lose, and there's a possibility that we may get back together in the future (he's moving) that's stringing me along as well. He's been with me through some of the worst times of my life and I can't imagine not having him around (I was miserable when he wasn't around over the summer). Does anyone have some advice? I really need it 😅 I don't want to move on but I know that I'm young and it'd be foolish to dedicate myself to one guy for now. It's almost like I don't want to accept that there could be anyone else better for me:((