It would be unfair to label it solely horror, though I certainly love to use ghosts in my stories. The difference is that my ghosts are just as likely to be the heroes as to merely serve as plot tropes. They're not always designed to scare, though if that happens to the reader, fine. To me, the mysteries of love, death, and faith, and the relationship between the three, are the most interesting things to write about. I still write some science fiction, I just haven't been as successful at selling it.
Every story is a learning experience, especially the failures.
I'm still too busy working on the fundamentals of writing to worry about what types of stories I should focus on. You've had considerable success recently in placing your short fiction, and you've written a few as yet unpublished novels. The fact that I've yet to sell a novel probably makes my advice somewhat dubious. But I believe if you want to be a professional fiction writer, it ultimately means writing and selling novels. I started a novel almost immediately after I decided I wanted to be a writer in 1996.