Nothing probably happened. You were most likely just unconscious on the floor. It's possible you had a self-correcting cardiac arrhythmia (if you were hit during the wrong part of the repolarization phase) or a petit mal seizure during that time (hard to say, postictal behavior probably looks quite similar to the state of consciousness following a high voltage shock) but obviously no serious neuro/cardiac damage, otherwise you probably wouldn't be here posting, unless your parents found you very shortly afterward.