Report her to the guidance counselor, make sure to say something like “I need YOUR help, SHE is making me very uncomfortable, and basing my grades off of something I CANNOT control.” And afterward make sure to say thank you a lot. What your teacher is doing is not okay, and it is something you physically cannot control, this is coming from another ADHD person who stutters very bad and fidgets or freezes when put under pressure, you cannot control it and she is doing the exact opposite of what a teacher should be doing.