Long story short, I have a moderate to severe case of PTSD in which I have a hyperactive startle response, especially when I am deprived of normal sight or hearing, to the point that I cannot listen to music with both earbuds in, for example. Three times this happened while I was having a flashback and I became violent before realizing that I was not in danger. In my Spanish class, we will be working in a computer lab in which I will have to put on a pair of noise-blocking earphones and sit in a three-sided cubicle with my back exposed. I really don't think that's a good idea for me, but I will likely receive a 0 for every activity I refuse to participate in. But I don't want to say anything to my teacher or the school because really, it's none of their business, and they will probably have to document it on my permanent record. So my question is: how do I get out of this without explaining the problem?

I should also mention that my parents don't know I'm still having symptoms (I was diagnosed four years ago). I would really like to keep it that way because they will probably try to make my drop out of the IB program and not let me go to college out of state in the Fall. I also don't want to upset them like they were when I was originally diagnosed.