I'm not attractive to guys?

I've been hurt before in a relationship, but that was when I was 14. I'm 17 now, and have never had another boyfriend. I've had a few hook ups, but they were meaningless and left me ashamed. And now... I don't know, I must just give off some kind of unfriendly air- or else i'm not attractive cause at parties I always get overlooked for my friends who are flirty and kind of easy. I mean, I think I look ok- I'm not hot, but being overlooked all the time really hurts. I'm the guy's friend, and I only attract men who want to make out randomly at parties, nothing more. I feel awkward when I get close to someone- like I don't deserve it! I immediately find something wrong with them, and stop liking them. It's really hurting me, why can't I be normal and go out with guys?!