Who Am I?

I clearly have been struggling the last few months but last night I realized something. I don't know who I am anymore. I used to be outgoing energetic and fun! Now I am more introverted and nervous to be around people. I need to find a happy medium and stick to it. I have never experienced that feeling of Who am I? And do I belong here? (At the party, not here on earth ;) I am confused but at least now I know what the problem is. Now to fix it!