Heya, I am a fellow sufferer of sleep paralysis, in particular I get horrible hypnagogic hallucinations along with being unable to move and stuck in a half sleeping, half awake awareness.
When I have an episode (usually in periods of stress, or when I am tired or sleeping badly) I feel an evil presence threatening me, a big black shadow man, a crushing sensation like a heavy weight on my chest, physical touches to parts of my body, voices or really loud crashing noises, and light patterns on the wall. I have also experienced euphoric sleep paralysis, where all the sensations are lovely and have even had orgasms in this physical state, so it's definitely something to do with state of mind around the time of the sleep disorder that affect how we experience it.
I went onto antidepressants at the beginning of this year to try to counteract stress/anxiety/depression/OCD which was causing the disorder to be so unpleasant, and it has helped a bit to calm it down. I started the last episode in about October last year having one a week or so, and by the end in January I was having it every time I tried to sleep, to the point where I was barely sleeping for the fear of it. I tend to have a few in one episode and then it settles. I do have a lot of nightmares normally anyway, and have long term problems with insomnia (which I can remember starting aged four).
One thing I have found useful is to understand sleep and how to foster a healthy sleeping environment. Knowing the facts about your disorder can dispel some of the fear. I thought I was going mad at the beginning of this year, I was beginning to jump at noises because I was convinced the dark man was real, so sleep deprived and anxious was I, it was getting difficult to differentiate between awake and asleep sometimes.
In the end, a good dose of temazepam was needed to really kick me back into a normal sleep cycle, and I've managed to avoid any more by taking a couple every time my sleep starts to get disturbed. Speak to your doctor, it's a valid health problem in my eyes and there's help out there for you if you need it..