I'm very selective about who I tell.
I used to be more open about it, but people would always assume they knew how to help me and they would end up making it worse.
It would always be, "Hey I know what would make you feel better, a noisy club packed with people who want absolutley nothing to do with you. Then we can find some girls that wont like you, or maybe you can look at some drunk idiot who will want to fight you for no reason."
Okay... maybe no one ever said those exact words, but you get my point.
I would say less than five people know how bad it is for me. And all five of those people know that I like to keep quiet about it, and respect my privacy on the really bad days.
I don't tell most people, because most people don't understand.