I'm sorry you got so scared. These are weird times, for sure.
I found this:
"When your body is subjected to stress, it goes into fight-or-flight mode. Stress hormones flood your body and speed up your heart rate, blood pressure, and your breathing.
Your body prepares to deal with the stressor, interpreting the anxiousness as a signal that you’ll need to stand your ground or escape from danger. Your muscles become primed to act, leading to a trembling sensation, twitching, or shaking."