I know this is a little unorthodox of a response. I also got really bad test anxiety. And no, burn out does not cause anxiety, it’s nerves. Here’s what i did:

Watch your caffeine intake. You want to dose it slowly and throughout the entire test. I diluted down an energy drink with electrolytes and water.

Breathing can help, but limited. Take the one minute break and take deep 5 second breaths. Don’t hold a section against yourself.

MOST IMPORTANT. I started taking Lions Mane, a nootropic, mainly for memory recall. But it also has a calming effect for me and cut my test anxiety way down. I don’t get overly jittery anymore. It’s really the key for me.

Hope this helps. I hate test nerves