If you are talking about when things don't seem real, when I am somewhere and it feels like I am floating and not connected to my surroundings, like what is happening around me is unreal. That is what I think derealization is. It used to make me stop what ever it was that I was doing. It gave me a sick feeling in my stomach, I would begin to feel like I was on the outside looking in. If I was in a place where I had to be normal I would try to get out of there and away from people and the surroundings. If I was alone I would think I was a going insane. It still is a frightening experience. Recently though I was moving in-between parts and I stopped for a moment, all of a sudden everything seemed unreal, just for that moment. It makes me think that when I experience the feeling of floating and unreal that it might be because I am in-between parts, that both parts are occupying the same space at the same time. I think it might be that. But I am not sure.