I'm proud of you! The worst part will be walking through the door. You got this thing. Even if you don't believe it, you are totally welcoming and sooooo easy to be around! You're going to have a blast and meet cool new people. You're the kind of person people want to be around!!!
I would want to puke, too. Just remember that everyone (ok, most.) there came without knowing anyone else at some point. Think of some conversation starters before you go, have a drink, and get on with your bad self. You can do this and you can be good at it.