I think I'm Haunted. help me please?

You are on the right track in considering this being sleep paralysis and Brittany is also correct in associating with the Old hag syndrome. There is an old legend that an old woman in tattered clothing comes in the room at night and sits on peoples chests and rendering them paralyzed. There is also a sensation of a sinister presence that accompanies this "Old Hag". What you describe of feeling a pressure when you are in this condition is common. I have had sleep paralysis several times and I can never get used to how it feels and how it can be distressing when you are experiencing it. I had one episode one time where I paralyzed and I could hear someone trying to break in my back door. I could not move or do anything and I knew that they were just about to get in and there was noting I could do. It was frightening. I even heard a laugh of some sort and it made it more intense. When I finally struggled myself awake , I had that same intense feeling of fright. It was so very real. There is a very good book I recommend Called "The Terror That Comes In The Night" by David J.Hufford . he describes in detail the Old Hag theory and many other supernatural assault traditions . Hopefully you can try to come to a better understanding of this phenomenon. It can be frightening to experience. Good luck.