Panic attacks suck.
I have trouble breathing in class a lot. It's been happening less as I've gotten a little tiny bit used to college... I had to run out of my only class I had my first semester. I was having trouble breathing and I felt nauseous, and I ended up throwing up in a hallway trashcan.
If I'm with a group of people outside of school, which is very rarely, a lot of times my vision will blur too... and things feel very unreal and it's really scary.