Exact same thing happened when I was in high school. We had to take self defense classes for gym, and I have PTSD, so nothing triggers it more then having someone invading my personal space and "pretending" to attack me. I ran out of the gym crying even though the teacher knew that I had PTSD, my mom told him not to make me do it, and then after he was like "You're being childish."
I feel your pain. All I can say is: Good luck.