Ghosts in lucid dreaming

Last week I entered a lucid dream cycle where I was in the same bed I was sleeping in, and I was "lucid dreaming" within the dream. I would enter these dream states within dream states by simply closing my eyes, and in many i would awake before dying or after being seriously injured (most of them were caused by me deciding to to put myself in danger).

In the last sequence I was "trapped" in my bed, I could not move or see much, I felt as if I was inebriated to the point of teetering between consciousness and unconsciousness. Suddenly I felt a strangle hold around my neck, but no one was there. The "invisible" person lifted me and proceeded to toss me about my room. I felt an overwhelming sense of having crossed into a "realm" I didn;t belong to; in my mind I agreed to leave if "he" would stop harming me. I awoke (now in waking life) very frightened and was scared to fall asleep again.

Anybody else have any similar experiences and have any tips? I have come to believe that this "ghost" was a manifestation of my subconscious fear of a dream world I can manipulate.