I've actually had this same problem, and I think you're getting a lot of good advice here. My wife (one of my players) noticed that I was getting frustrated while planning a game, and when she talked to me about it, I said that I wasn't enjoying planning, but that I still wanted to play, and to hang out with friends, and that if I didn't run anything I was afraid that the group would fall apart.
What she said was basically encapsulated by what Orchomenos said:
Originally Posted by Orchomenos
go back to the basis. Do something YOU like, the way YOU want it.
For me, that meant getting back to basics, taking more control of a story than I had been (her words were that the game needed one DM, not five DMs), even if it meant sacrificing some of the player freedom I had been allowing.
We're just anonymous talking heads on the internet, so it's up to you to decide what to do- but I think if you're burned out on running games, maybe you should tell your group exactly that, and say that someone else needs to step up and try a game, even if they need help running it, because you need a break. If they're not willing to do it, then suggest board games or play something that doesn't need a GM, or even just take a break for a little while. The last one (taking a break) is the hardest, because it will usually mean that the group stops playing together, as people will find other activities to take up their time, and then have to change gears from those activities to come back to gaming.
If you're open to it, there are stores that run public games, and you should be able to jump into a weekly game and just relax and let your brain unwind.
Hope it works out for you, Mick.