I had the exact same experience. I remember being in bed for what seemed like ages and would only feel numbness and heaviness, but, I never got vibrations and I was still able to move, etc.... I originally thought it was SP, until I found out it wasn't but the early stages. I found that if I ran on the treadmill a couple of hours before bed, then I'll get to SP that much sooner and easier. Infact, I started feeling vibrations when I really pushed myself on the treadmill(shouldn't have though, lol

). In some of my cases where I was in the pre-SP stage, I also felt my hand floating like in your case. I automatically thought that it might be my astral body so I stopped, but, I wasn't even fully in SP, so, I can't really comment what it was

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