Jeeze Caitlin that does sound frightening. And I don't think you should be too harsh on yourself for how you reacted. You don't have much control over it.
A girl I knew had epilepsy and she had a fit while we were walking to class, there was no one else in the corridor. Anyway I just stood dumbstruck and watched her, I didn't even get anyone. She was a bit of a bitch to be honest.