There's a story about Helskinki bus station. Because of the location of the main bus station, all the buses travel in the same direction for the first three stops before branching off to various parts of the country. So, for those first three stops it feels as if you're not getting anywhere.
Now imagine that this is a metaphor for your career. Each bus stop represents a year. We all start in the same place - the bus station - but we board different buses. After three years however, it feels as if we're not getting anywhere so some of us choose to hop off the bus, go back to the bus station, and try a different bus.
You started on the writing romance bus, but that didn't work out so you go back to the bus station and try the thriller writing bus. After a couple of years, that seems to be heading nowhere fast so you hop off the bus, go back and start again with romance. Or non-fiction. Or short stories. Or poetry. Or script.
Stay On The Bus.
Three years might seem a long time, but in terms of a career it's nothing. It took me five years from starting to writing fiction seriously (by which I mean, every week I wrote something) to getting my first book accepted for publication. If I'd given up at the three year point, or shifted to a new genre, then all that previous work would have been lost.
It takes time to establish yourself. Just accept that, and keep going. Stay on the bus.