I agree with others here who say to avoid thinking/reading/writing anything regarding lucid dreaming, sleeping, dreaming in general, and reality checks. Another thing to do that has worked well for me when I awake in SP and see/sense an evil presense is to:

1)recognize that it is simply SP and that you should just relax and imagine you enjoy the experience. then

2)imagine you are somewhere peaceful and calm. I like to imagine laying on the sand in the beach watching the ocean. Imagine being there and feeling the warm sand. What will likely happen is that you will enter into a dream on that beach that is peaceful.

You could also try telling yourself that you fear nothing and truly believe it when u say it to yourself over and over b4 you sleep. It may help to eliminate any thought of fear or nightmares because when you think about those things (and you seem to be consumed by those thoughts) you are going to have nightmares when you dream.

Good luck, I hope you figure things out.

And btw... it's not the devil or something evil for real so don't worry about it.