I got completely burned out about 15 years ago.
I'd been role-playing and GMing for 20 years, I'd gone through the highs and lows of becoming a game developer on one of my favorite games and then seeing it closed down due to the owner losing money because of the Asian financial crisis (1997), I had been intensely involved in online discussions on Usenet (including acting as a company's liason to the fans), running games at GenCon Milwaukee for years, and on and on.
One day I was setting up for a game in my basement (running D&D 3.5e, using the Dwarven Forge stuff for the dungeon). I looked around and realized I wasn't having any fun at all, and hadn't been for a long time. I was just doing it out of obligation. So when everyone got there, I went ahead and ran the game and then let everyone know that, as much as I enjoyed their company, RPGing wasn't for me any more. I would no longer be running or playing games. I was out.
The group was comprised of good friends and some family members, so they understood. We eventually found other things to do together and had a great time.
I put all the games away and didn't buy anything new or even keep up with what was coming out. And I stopped participating in online forums about gaming.
It took me about 10 years before I had that old feeling, wanting to run a game. And it's been great since! No feelings of burnout at all.
But it did take time, and stepping completely way.