Not to worry. It's happened before. There's a 60 percent chance it'll happen again. Doctors don't know what caused it. Therefore, don't worry. "No cause for concern." Seriously, that's what they're saying.
What is a seizure? "A little storm in the brain's electrical system," saith the Associated Press. Apparently, practically no one understands whither, why, or whence?
Having more than one seizure technically makes you an epileptic. But not to worry. Absolutely NOTHING to worry about.