Same Dream Twice

I don't usually remember my dreams once I wake up. However, this time I did remember something about the dream. I remembered being confused in my dream  - a “what the Hell” moment. I was having a dream that was playing simultaneously. It was the same dream, but it was playing in my head twice, at the same time. Like if you have a screen and read the same document side by side.

This has never happened to me before. Not ever. It was the weirdest thing, it concerned me, and I wanted to wake up. But I was too curious. Why was this dream, which I can't remember, playing in my head like this?

When I woke up, I made a point of remembering that it was playing side by side, but the content of the dream I could not remember