I can totally relate to you, armos. Just about everything you stated describes me. I too have social anxiety disorder and it is a living hell. Nothing is better than failing to introduce yourself in front of the class, failing to do presentations, etc. I too fail with females and never had a girlfriend. I was almost in a relationship with an extrememly beautiful woman, but my SAD and clinical depression (and my occasional serial killer look) got in the way. Honestly, I don't even remember how I had the balls to get that far. Also, someone here said that women are overrated, and you can live happily without one. He is a wise man.
As for the part where making friends is difficult, honestly, the only advice I can give you is to force yourself to approach people or talk to them. Trust me, I know how much of a bitch it is. It's not easy, but it does get a lot better to socialize with people. It doesn't even have to be an all out conversation, just try making small talk. If making friends is a bit out of your comfort zone, try making aquantences instead? It's much more comforting imo, and none of those trust issues are invading your mind.
I hope my comment helps you, mr. armos sir.