Murmuring voices

Many years ago, probably in 1997, I had been going for a long time with very little sleep. Finally, I took a short nap. When I woke up, I heard what sounded like a huge crowd of people talking to each other. I couldn't understand what was being said, though. It was just a lot of murmuring sounds, with some voices momentarily becoming louder and then falling back into the background murmuring. No matter how loud a voice became, though, I could never make out any words. I walked around, but the sound followed me whereever I went. I was vaguely disturbed by it, but also amused. I felt that it was some side effect of my exhaustion, although I have been exhausted many times before and since. Perhaps, instead, the exhaustion allowed a breakdown of barriers and some kind of psychic manifestation occurred. Who knows? I finally started doing something, and at some point the sounds went away.