I've never been in your position in my 25+ years of gaming, but I think that's because I play so many different genres. And have hobbies like crazy too (but that just means I'm not exceptionally good at anything).
I like to play FPS, TPS/action, open world, racing/driving, RPG (hack'n'slash and Turn-based), horror, and a few indies here and there. What I'd start by doing is maybe expanding your gaming horizons, getting out of your comfort zone like some have said. Talk to people to see what it is about the kind of games they like makes them tick, and you might just catch the same bug.
Another thing you can do is organize your gaming library. Well, in Steam at least, you can make folders. Games that you want to finish first and foremost. The ones you don't want to see again, just put 'em in a FINISHED folder. The rest, just categorize however you want.
And lastly, yeah hobbies do draw your interest this way and that - I've been torn between games, martial arts, music, movies, comics, and racing/car scene for as long as I can remember. Whenever I spend too long away from anyone in particular, my itching to get back to it grows. I believe it's probably healthier, too.