Something I didn't expect after the car accident was to experience short-term PTSD. Apparently, it's not uncommon, especially for individuals with a history of trauma and abuse.
Fortunately, I have WAY better coping mechanisms than I did when I was younger. I've been able to stay calm on the outside and tell myself: "This is literally just cortisol. I am not in danger."
I've been drinking water, breathing deeply, and using grounding exercises. Wish younger me had known how to do this stuff, which is why I'm sharing, in case it might be of help to others.