You've got some kind of reflex in your head that's making you think no girl will ever want to be with you. And with that kind of attitude I don't think any of them will.
I don't know if you were traumatized or something by a past mistake with a girl, but you need to understand that people have flaws. One of my girlfriends, for example, had this gross slurping habit. I didn't like it at first but over time I was able to ignore it. You have to brush that kind of stuff off and focus on the positive.
Girls are remarkably good at knowing what you're thinking. They can just TELL when you're thinking negatively. And they're gonna mirror that and make a negative opinion about YOU. Conversely, if you seem bright and interested, she'll respond positively.
And so what if one girl doesn't work out, there's millions of others out there. Whenever I talk with a girl who's a total stranger, even if I don't get her number or never see her again, it's great practice and leaves me feeling pretty darn good.
Giving yourself an image change would also be a great start. If you're fat, lose weight. Get a clean haircut. Throw out your logo and band T-shirts and get some polos and khakis.