Never tried to shift, what was that

I was never into shifting. I practiced Neville Goddard technique SATS for manifestation. And I had one crazy incident. Im wondering was that what you all call shift. So I visualised the desired scenario I wanted to manifest. I did that for many night in a row. One Sunday i had nothing else to do. I was just kept lying down, Im not sure every one or two hours and would visualize my "scene" again and again, all day long...then again at night when I went to bed.

The scene almost automatically "looped" as I drifted to sleep. Suddenly I was "awakened" (still asleep though, lying in bed) by "myself" who was sitting on the bed, "I" told me: "you gonna see now". So at that moment I felt like a vacuum on my forehead (don't know how to describe it) and all went black, the last sensation of my body lying on the bed was feeling my jaw dropping like paralyzed or something. Then it was all black no sensations for a moment. I regained consciousness opening my eyes in "myself" in the scene I was imagining feeling the whole body...I freaked out...as much as a human can freak out. In the scene the moment I came into "my" body I was sitting on a chair and drinking water. I immediately put down the glass stood up, closed my eyes (i was completely freaking out) and started yelling go back, go back....then I heard noises like tunning a radio...and next thing Im in my bed, eyes opened and my jaw opened as was the last sensation when I left (?). I never made any sense out of what had happened. It was real af. It wasn't just vivid imagination, i felt my consciousness leaving....And the most frightening part was my jaw dropping like my body that I left behind was dead. Im curious was that a shift or what the hell was that. Could I have just stayed there? Anyone experienced anything similar?