I had this exact same thing in secondary school during about 5th and 6th year. For English class specifically because someone would be asked to read out their answer everyday without fail (a bit like Russian Roulette to me). Was asked about it one day by the teacher and wasn't called upon for reading out from then on (while still having the option if I felt up to it). Disclosure like this definitely helped and I felt far less anxious every day from then on.