I’m sorry this happened to you and I understand it: that was my entire school experience, and it was awful. What people don’t understand, is that this kind of approach only traumatizes you. You don’t learn to relax by having a panicked experiment, but by facing mild discomfort and seeing that it’s alright (such as stuttering a bit in front of a small group, or a single person in a non-threatening situation). Can you talk to your teacher? Or ask your parents to help? Again, massive anxiety does not help.