The GREAT HollaAtUrBoy2 senses your dilemma and offers the following advice:
Go in whatever you would feel comfortable in. What ever you would wear to a dance at school, let's say, then wear that to the club if you wish. There is no dress code, just wear what you want. I wouldn't recomend clubbing in your formal-night dress, unless they are having a "prom" theme or something of the like.
The GREAT HollaAtUrBoy2 was pleased to offer his GREAT advice. Enjoy yourself.