Response:

One can never say with certainty exactly what such an experience like yours was, but that sensation of a current of energy moving through the body fits the description of what wisdom tradition would call a kind of shakti or kundalini experience. It’s a sort of physical/energetic sensation or activation that can accompany the expansion of consciousness. It frightened you because it was so intense and foreign feeling that the only association your mind could come up with is that you might be dying.  But you weren’t, you were actually becoming more physically, mentally and spiritually alive.

Love,

Deepak