It sounds like a dissociative state. I sometimes have a similar experience when I am in between alters. I know that sounds strange but sometimes I will start to switch but I don't. I just end up in a disconnected, emotionless state, where sometimes I can't feel the chair I am sitting on. Not like I am floating but just not feeling the chair. When I realize that, I usually have a feeling of fear that follows and than I switch. Because fear can cause me to switch. At least that is how I understand it. I have had this state last a few minutes to a couple of hours. Before I knew I was DID I just thought I was loosing my mind.