Depending on what level of school ur in it’s really worth it to talk to the school about accommodations if you think that will help! I get extra time so I don’t have to worry much about time and I go to a different quieter room. I also listen to frequencies by “miracle tones” on Spotify and try my best to just focus on the music and push away any incoming thoughts. It took me some practice but that usually works well for me!
I'm also in college! Assuming it would be a similar process for you, I made an appointment with the disability office and they had me send in a letter from my therapist! I have the extra time, different testing location, and the ability to use a recorder during class (if ur professor doesn't post lecture videos). The recorder is especially helpful for me! I get a lot of anxiety during class about writing notes down, but I'm not able to focus on actually taking in information.