Sylvia Brown would say you were having a out of body experience.. I forget the name she calls it. That means it is actually YOU. Your spirit has been out of your body and flown around and was trying to get back in. I think you are suppose to ask (before you go to sleep) God to give you a smoother entrance back in after you have left your body. Here is just a random thing I found when I typed in living/outofbody/experience
http://healing.about.com/cs/spirituality/a/obe.htm

This guy believes we all do it every night..
http://paranormal.about.com/library/.../aa110501a.htm

I have told the story here before of feeling someone tucking me in one night when I was living with and taking care of a friend of mine, who's friend had died and left her his house. We moved in to take care of his cat Jenny, who slept with me every night. I thought it was Mary tucking me in and opened my eyes to tell her "Thanks" and there was no one there... but the covers were still tucked in!

Several days later I mentioned to to her what I had felt and she told me she had the same thing happen to her and she thought it was me.