I'm sure most of us have gone through periods where you just don't care about the games you're running and prepping for that next session feels like doing homework for a school assignment. I've been in that mode since January. Happened to me in D&D after Christmas and that ended. I thought about just dropping Mouse Guard before it even started when it became so hard to schedule that first session. Fortunately for me, two of my friends' enthusiasm to play kept me from just scrapping the idea. We finally all sat down to play after over a month of rescheduling. I'll be honest, up until the moment that we started to play, I was just kind of there. But once we started role-playing, I might have been the happiest guy in the world.
Sure, prepping for a game can be a huge chore but to be able to escape into a make-believe world with them for a few hours makes it all worthwhile.