I Am Afraid That I'll End Up Alone

I'm 30 years old and i'm single for 2 years now....... I am someone who has a very low self esteem and that's why i'm really really afraid that i'm going to end up alone. I'm the kind of guy who's just too nice and always ends up being the friend or getting stepped on and used. I can't talk to girls in a bar or something like that, because i'm scared to death i'm going to be shot down or that they ridicule me. I've only started dating when i was 21 and I've had like 3 girlfriends ever. And they all were in my class. But anyway, that was pretty much my story....