When I've been hit by cars, I became silent and felt worthless or helpless for the next week. To my body, the car was a tiger that had been stalking me and had picked me out as prey. I got away the way I learned how to with the other tigers in my life (my abusers, tornadoes, etc) -- I cooperated, I got out of the way to make room for the tiger to rampage, I hid my injuries so the tiger wouldn't notice and come back (from an abuser complaining if I showed pain, for example), I apologized to the tiger if the tiger noticed me to help make sure the tiger didn't feel bad and try to bite again in defense, and then I spent the next week feeling shitty because the tiger was still out there and I hadn't done anything to get rid of it or yell to scare it off.
There's a doctor in anesthesia who I don't particularly like watching and therefore haven't for a long while, but he sometimes would say things like, "I know if my patient has had trauma in the past because when they wake up from the anesthesia with a new wound and confused from not being asleep but having their brain OFF (and turned back on one section at a time), they become tricky patients. They accuse staff of having not really done the surgery if in the past doctors didn't believe them about their illnesses, they start to cry terribly if they think we're going to hurt them while they're so vulnerable, they become aggressive and angry if they have ever had to fight off someone of their life or the life of a fellow soldier," etc etc etc. Aka, as the brain comes back after literally being put on pause, if it has been wired to react to danger often enough, it will attempt to perform those behaviors that as MUST worked for survival in the past, all while you're confused and won't even remember what happened later.
I'd take a look at your past tigers. This tiger might have revealed something to you about how you're coping and what might need some extra care.
Being hit by a car is stressful. Accidentally calling your teacher "mommy" is stressful. You don't judge a kid who starts absolutely sobbing if they make that mistake, even if the reaction is unexpected and not typical.
And typically it take 18 months of straight practice to start re-wiring a brain to even CONSIDER a different way to deal with the next tiger in your stress cup.

This is why people with co-occuring addictions with their mental illnesses have such a hard time, too.
It's not hard to see why this has you stressed out, as this would stress anyone out! I'm sorry that happened and I hope you get to feeling better soon
Maybe it would help to try to practice in your mind how you would like to react? Like, what would you expect a person to do if they came up to you right now and took you they just also got hit "gently" by a car?