Dreaming under anesthesia?

Several months back, I had surgery. When anesthesia was administered, I had the strangest experience, and I am curious if there is a precedent for this. As the anesthesia was taking effect, my head felt heavy, I slurred words, and I felt myself losing control of my body (nothing out of the ordinary). But I wasn't going out. I saw nothing but white, and while I could still feel somewhat, I felt removed from my body but I could talk and was maintaining some verbal contact with the surgeon and nurses. Then I started to panic, as I realized I was not losing consciousness. Finally, I felt myself go out, only I didn't really. I kept having the sensation of going out, only repeating over and over. Then, I had the strangest nightmare. It was almost like an out of body experience. Everything was white, and there were strange fragments of memories that made no sense. Finally, I ended up talking to somethings, and they made it clear I was in Hell. However, it was a Hell of infinite nothingness. ?