Feel you bed shake and your not doing the shaking

Sounds like some paranormal, ghost in da house, demon a creepin, lady in a white dress singing, chandler swinging, banshee screaming .... possession.
If you do any kind of voodoo, ouiji board, satanic rituals or look it up online. You'll tend to find your bed shaking without you trying.

Or if we want to be scientific.
You could live by a railroad and the vibrations from the train make your bed move.
You're house is over a seismically active area and you're experiencing tremors every night.
Your washer or dryer shakes the whole house.
Or your having faux feelings due to drugs you take before bed (either prescribed or recreational)

Do you have a poltergeist?