Okay one day I had come home from school and I was exhausted and after I finished my homework I took a nap well I had a very bad nightmare about demons and I awoke (or at least I think I awoke to my mattress shaking and then it also felt like the mattress was breathing and I wanted to get up or scream but I couldn't I opened my mouth and no sound came out it was scary and then I closed my eyes and opened them again and nothing was happening that's why I don't know if I was dreaming or not, but after I opened my eyes it felt like there was a presence in my room I was terrified because I had no idea what I experienced, I didn't understand it and a couple times after that day I felt my mattress shake for a couple of nights afterwards and I was fully awake.its been about a month since that has happened and I have had no more experiences was there something or was it a dream?

I have experienced the same thing about 4 times in my life. I was told they are panic attacks brought on by extreme stress. The symptoms are almost exactly the same, but I'm not a doctor. Maybe see a specialist?

Thanks that may be it :]

Ive had dreams of a demon and its always the same demonic face I see whenever I have a dream about it. As far as the otger things you said, about being paralyzed. There is a sleep condition its called sleep paralasis its easily curable with certain sleeping meds. But dreaming of demons is definitely not normal...