How can you stop thinking about a girl when you know she has a boyfriend and you have no chance at all?

Let me just lay it out there for you. I met the most amazing girl since I started college over two months ago. We have a lot in common. When I mean a lot, I really do. Up until the point it is almost scary how much we are alike. We chat quite often (basically everyday), and I do enjoy that. Occasionally I go to her place and we listen to music all night. And just talk.

I don't know if I am in love (you give me a good definition of that feeling, because I don't know). But I just cannot get her out of my head. I already have trouble getting to sleep as it is, but the last few weeks have been even worse. I know that she has a boyfriend back in her hometown (she goes there in the weekends (I go to my hometown in the weekends too)). However, even though I know this, I still can't get her out of my head.

I don't want to tell her how I feel because I don't want things to get awkward between us because I really enjoy hanging out with her, even if it were to be as just friends. And I also know that she doesn't like the town we both go to college in (for reasons, not the study itself), so I know that she is not going to cut herself off from her hometown (and surely not for me).

Rationally, I can accept the fact that it's just not meant to be. But something in me is not accepting that, and it's costing me a lot of sleep.

Some advice might be helpful, thanks.