How to say this to my professor?

Hello, I am a student of Japanese and I was wondering how say say a specific phrase to my professor. I keep freezing up in class due to social anxiety, and they keep believing it is because of me not understanding what they are saying. I have tried to explain it, but I’m not entirely sure how to say that I have social anxiety disorder in Japanese. What is the correct term for it so that I can try to explain it to them? We have to speak in only Japanese in the course, as it is full immersion.