The Paranormal and Sleep Paralysis

The first encounter happened to me about five years ago when I was in high school. A small creature, maybe about three feet tall, with grayish, slimy skin appeared under my bed as it hissed at me and disappeared. This is still the same house that my last experience had occurred in. One of my dreams I got this intense pain in my stomach like I was going to be sick and my insides would be ripped out. It was such a strong pain that it jolted me awake. There was this dark grey blotch on my ceiling that almost looked like TV static and in the dead center was a face - Jack the Pumpkin King grin.