Hun, don't be so hard on yourself. We've all had those moments. I don't really have that bad social anxiety but even still I don't think I could handle a night club. All the noise, people in one small area. Try to work your way up to that kind of event. Stick with smaller things, a movie, a mall. That way you can predict to an extent how busy it will be and work with what you are comfortable with. I've learned through experience throwing yourself head first into a high anxiety situation doesn't cure you of it.

There is no such thing as normal. If you feel bad about the night, maybe treat your friend to a coffee, girls/nail day, or whatever you'd like.