I Need to Learn to Move on

I know relationships aren't that big of a deal but I need to vent about something. Basically, I'm insane, I had a boyfriend over a year ago that I can't seem to move on from. When I like another guy I forget about him but I always come back to thinking about him. Last fall I began having dreams involving him every second night for about two months which of course caused me to get very confused. I started talking to him a little bit and eventually told him I still liked him. He told me that we weren't right for each other and that it just wasn't going to work. I thought I had moved on but now here I am again. I keep remembering stuff from when we dated and how happy I was when we were together. I know nothing will ever happen with us again yet I keep deluding myself in these fantasies where we do get back together and it's very unhealthy to keep thinking this way. It should be known that he doesn't even trigger my fantasies as I hardly ever see him at school and the only thing we've said to each other since we broke up is hi. Obviously, I'm just going crazy and thinking up all these stupid things on my own. I mean I kinda know why I do this since I've always lacked closure from him since I was the one who broke it off and I have a lot of pent up feelings about it but it's still crazy. I really just want to move on so I can find someone who really likes me instead of being caught up in this nonsense.