This has happened to me once, I was sleeping and I was floating around myself and looking at myself while sleeping. For what I know some people and I'm quoting "have the ability to go out of their bodies during their sleep" I don't know how it can be done, but it happens. What I do when i get those strange feelings is that as soon as I wake up and do some meditation. For example: Concentrate in your breathing, inhale and exhale you will find yourself in great state of mind, you will basically clear your mind of tension and problems and then you will again sleep peacefully. You can use this method before going to sleep. I hope this helps.