Can you help me?

Ok help me figure this out. I'm half way between sleep and wakefulness. I start to feel and "hear" a strange swirling noise in my head. I can also feel a funny vibration going on in my torso area. I'm on my side, if I lay perfectly still, my body will go limp, paralyzed and I won't be able to move it for awhile. I can sense my spirit maybe leaving me almost like when a person dies but I try real hard to stop this by shaking a limb vigorously. If I try to go back to sleep this same funny occurence will happen, but it happens less frequently when I'm on my stomach. What is going on?