Strange sensation in belly while attempting Astral Projection

Hello yall. Last night I gave it another go to try to Astral Project. I have been practicing for many years now, and had mixed results. Last night, as I was halfway from being sucked from my physical body, vision shaking violently, I felt a sudden pang of white energy hit me dead center in my belly. I think it was enough to shake me and my projection failed. Does anyone have any insight? I have never felt anything like it while in trance, projecting or not.