I don't want to use this guy, but how do I get over a guy I used to really like?

There's this guy that I really liked last year (Paul) and he liked me back. He's like the typical Mr. Popular. Long story short, he turned out to be a total creeper/d*uche and I just couldn't get along with his friends AT ALL. So nothing really happened, even though everyone thought something would. Anyways, this year we're in the same AP lit cl and he sits with this slutty girl. Plus his best friend is in this cl (cool). So there's this guy, Damien that I sit next to everyday and we've been good friends since freshman year. He's really sweet and cute and all these girls like him. I semi-liked him but I always liked Paul more. But this year, I don't want anything to do with Paul (even though I've kind of started liking him again :(, so I've been like trying to make myself forget about him by flirting with Damien. I know that Paul hates it and so does the slutty girl because they always stare at us. I've begun to start to like Damien, but I always end up liking Paul more. I don't want to use Damie, but I feel like I am, even though I want to get over Dom. How do I fix this situation? Help!