This has happened to me only once, and I was TERRIFIED to go back to sleep that night and several nights afterward. When it happened to me, I felt like I had woken up, and I was trying to say "help me", but I couldn't speak, so it came out garbled. I said it about twenty times, and right before I woke up, I dreamt that my husband woke up and just looked at me, and I was thinking, "WHY ISN'T HE HELPING ME?" Then, the last three times or so I said "Help me" I actually said it clearly, because my husband had awaken, and shook me awake. He said Iwas talking in my sleep and I actually WAS saying it GARBLED! I was convinced that it actually happened for a few days, until I realized that in my dream, when my husband woke up and was looking at me, he was combing his hair with a small black comb. My husband doesn't OWN a small black comb, and he doesn't keep a comb on our headboard. It was then that I realized it WAS just a dream, a very scary one at that...and although I was still afraid I would have it again (because there WAS a sensation with it, a kind of cold, tingly sensation as I was going into it, (and you're right, I didn't realize I was asleep at that point-I thought that WAS when I was falling asleep) that made it even scarier), I was able to sleep better knowing it was a dream and not some weird phenonmenon.
