Sleeping

Does any of this happen to you when you're about to fall asleep?

-All of a sudden it feels like you're slipping down towards the foot of the bed, but super fast..
-Out of nowhere, you hear a loud sound, but you realize you only heard it "in your mind".
-You've fallen asleep, you wake up, you're looking around, but you can't move your body.

I haven't had these experiences in a while, but they all happen to me occasionally, and on top of that, once in a while I feel as if someone just slapped the top of my head.. Yeah, I sound nuts, I actually opened up to my co-worker and told her the above, and she told me I was just imagining things, or only dreaming them. But I'm telling you, it's not a dream, and it's not my imagination!