I think it just takes time to adjust, and to heal. Not to mention it's the middle of winter--I always get the blahs this time of year. Even Florida's had sort of a sucky winter from what I hear.
Go easy on yourself, and don't expect to be all better overnight. It WILL get better, promise.
How about finding a group activity that is less intense than improv? Maybe volunteer work? It would get you out and around other people without so much pressure.