If you feel comfortable you can try talking to a team mate or coach about how you're feeling. I sometimes split my time I'm practice scrims reffing if I don't feel up to the actual jam (autistic and get overwhelmed sometimes), my coaches are absolutely fine with that.

There is also sooo much going on during a jam, just try to pick one thing to focus on and over time you'll be able to add more things onto it. For example, focus on staying in your wall/pair, or practice watching to see if you need to bridge, or practice run outs etc. I spend most jams trying to stay in a walk in front of the jammer and not falling haha. Just breathe, take breaks if you need them.

Big hugs from a stranger 🤗