Because I don't have enough writing to be doing?

I had an entire world basically poke its way into my brain. I've been typing notes as fast as I can around work and sleep over the last couple of days. It is an original story, and it is NOT my usual stuff. It is way, way outside of my usual comfort zone. I'm not sure what part of my brain it came from or why, but I'm trying to get the information down so I can see if I really want to write the story.

I'm not sure if it will end up being horror or just fiction, but it is not a happy world; there will be no "happily ever after" here, particularly for the female protagonist. If it were a movie, it would probably end up a heavy R and probably further. That is so NOT me.

It is so far out of my comfort zone that I am unsure if it is a chance to grow, or just trying to clear stuff out of my head to let other creative ideas flow.