Most Helpful Guy
One step at a time.. I know the feeling.
Start by making friends at less noisy environments. Clubs aren't really a place to make new friends from scratch, but to go to with some people you know.
Just take baby steps in acquiring quality friends first through areas of common interest. If you join a club or go to a gym you might meet some people with similar interests. Strike conversation, use a nothing to lose attitude and you will make a friend or two.
Then build this up through reciprocal invites for dinners/birthdays and gradually a social circle will form. You will get to know their friends too.
And before you know it you'll be meeting others who want to go clubbing if that's what you wish and go for it!
Your EXTROVERT self will return, she's just on a temporary holiday, that's all.