I hate to break it to ya, but the paranormal ain't real. If it is really a demon, stop worrying, bring in a scientist, and make millions proving it to the world. Trust me, I would be too excited to argue if you have convincing scientific proof, and you will likely be too rich to care.
To be completely honest, making yourself believe it IS paranormal, will probably make the "manifestations" worse.
Now as for the issue... well. Most dreams relate to real world stuff in some way. What is actually bothering you in the real world? Often reducing stress will help in my experience. If its really bad, you might need to see a professional.
edit: If you have experienced traumatizing events, you really ought to see a professional.