Do I have social anxiety?

I am very anxious when I'm with people that I don't know at all, or very well. I constantly feel judged by them so then I just don't talk to anyone unless they talk to me first and if I always reply with short one-word answers. But then people judge me for NOT talking, so I try to talk to people but it just ends up really awkward and I beat myself up about it, and the cycle repeats it's self.

HOWEVER, when I'm with my friends I turn into a completely different person; I'm loud; I'm funny; I'm not ashamed; I'm wired; I'm stupid; I'm smart and I'm bitchy.

The only way that I can even stand to be anywhere public is if I keep telling myself that I'm useless; that nobody gives a sh*t about me; nobody will ever give a sh*t about me.