The best advice I can give is to start looking somewhere else for dates. I always thought High school was not the best place to start relationships thanx to social politics and other crap like that. you will be more successful in college. I've seen guys from my school who couldn't get a girlfriend for the life of them, and now they're in college and just always surrounded by a posse of girls. I was quite shocked, actually. But there you go, it will happen for you eventually. i'm not saying you have to wait till college!
I think you need to get yourself out there, like join a youth group or something or get a job that demands from you to be social and work around a lot of people. It's even better if they're not kids from your school or anyone you know at all! You'll feel like a new person and it'll give you confidence to start over. You need to surround yourself with possibilities first, and something will happen for you.