Large crowds was a problem in my last of high schools. It was so overpopulated, that during lunch and inbetween classes, the halls were so full, that if you speed walk like I do, you just end up having to go through a bunch of crowds, making a lot of physical contact. That with the sounds, lights, smells, and everything else in a high school made my senses shut down. I had no energy to get anxious, but when I am in these crowds for extended periods of time, I would get anxious because it felt like I couldn't get out. Further more, I could not participate in any school-patriotic assemblies held in the gym, because the first time I went, I got sick for the rest of the week. It was okay in our theatre hall, though, still pretty bad.
Because of shutting down and getting overwhelmed easily, I found that my anxiety was because I had no escape and did not want to suffer through this shutting down as often. Now imagine a couple of 9 hour shifts as a cashier on top of all this and yeah... I was in pain all the time, I was cranky, I made a lot of mistakes, I couldn't think.
_________________
--- ?Be who you are and say what you feel because those who mind don't matter and those who matter don't mind. ~ Dr. Seuss ---