I don't think there is anything wrong with you. Your first problem is probably where you are looking for girls. Bars? Clubs? I'm pretty sure you know what kind of girl you will find there. If you are not shallow, like you said, then look for a girl at work, a coffee shop, somewhere with intelligance and perhaps arts. You never know.
Don't put too much pressure on the issue of having a girlfriend. Girls can totally pick up on that needy/pushy aura.
As for trying to doom the relationship for no reason, maybe you are feeling insecure for some reason. (We all do it.) Maybe you are afraid of being dumped for some silly reason and you feel that you must find fault first, so that you won't get hurt.
Long story short, you just need to relax. Look for girls in a more fitting environment (for the type of girl you like), not the bars/clubs. Be yourself, because confidence is super sexy. And just hang in there. It will happen when it's ment to happen. =)