One side effect of digesting an overwhelming mean might be heartburn or indigestion. Similarly to that, you have flashbacks while your mind is trying to digest your traumatic event. Re-framing your experience can help somewhat. Most people are horrified by their flashbacks and judge them as symptoms of 'craziness'. That simply is not the case.
Flashbacks are healthy and normal.
Self-talk also works somewhat. Then you make statements to yourself as if you were your best friend. You are safe now. I can take care of you.