Freeze

Another response to danger is your body hitting the pause button altogether. The freeze response involves becoming immobilized or “freezing” in response to a threat. This can involve a state of paralysis or being unable to move. It’s thought that this response might have evolved as a way to avoid being noticed by a predator or to remain still in the hopes that the threat will pass by.

https://health.clevelandclinic.org/what-happens-to-your-body-during-the-fight-or-flight-response

I would suggest emailing improv groups around you to see if you could join a class that’s supportive. Make sure to ask the teacher ahead of time so you can get a feel for if they’d be good for you or not and if they’re willing to work with you. If you could take a friend that’s interested as well, that would help for you to work with someone you trust.