I've had terrifying sleep paralysis, with swirling voices whispering around my head.
Most of them were when I was around my teenage years. However, I had one the other day after meditation where I felt my cat press next to my body...yet he was not in the room with me. That seems to be common when I have them, feeling or seeing presences that aren't there. I was a little freaked out, but I've become more familiar with that state so it doesn't scare me as much.
BTW, if there are vibrations where you think you might separate from your body, the log-roll out works well
Satyalok