Hey Rst,
Classroom panic attacks are the hardest on me as well. In fact school was where I learned that I had panic disorder. I know it is really hard to do, but letting your teachers know is often an excellent thing to do. Most teachers will do anything and everything they can to help you (whether that means letting you sit at the back, or letting you leave without an explaination). Personally, once I had told one of my teachers he became more open to me, and often encouraging my process on this steep learning curve.
I know you are really nervous about people at schol thinking you are weird, but in truth most highschool students are worried about being weird themselves. One of the hardest lessons to learn is that what poeple think will not kill you, nor will it matter 5 years from now when you will have moved beyond your school.
Good luck, and if you need to talk to another student, just reply to this post and include your email address, okay!?
Roses