It usually happens when I'm around a lot of people.. not so much like walking to class or anything, but a more energetic environment - like watching a show at a club or something like that. Other times it happens when I'm at home and I'll suddenly feel completely overwhelmed; like I'm going crazy or something, and I can't sort anything out in my head. I end up getting sort of dizzy and sick, and it's a lot harder to breathe. I don't have asthma, but it seems somewhat similar. It usually helps to sit down somewhere away from anyone, but it takes quite awhile until I can breathe normally again. I don't know what else to classify that as.. what do you think?