Was taking antibiotics for bronchitis had diaherria for3 days i fainted but also rember shaking uncontrollably was that a seizure?

Seizure: Less likely a seizure since you remember the event. Seizures of tonic/clonic (shaking) generally cause loss of consciousness. Would favor rigors if actively being treated for infection with an antibiotic. There are some epileptiform reactions that do not cause loss of consciousness, however, and would require consultation with a neurologist if they occur more than once.