Jeff Lembeck has a post on The Pastry Box talking about burnout:
Burnout is real. It’s part of this job and is part of any job that I’ve ever had, and it’s really hard to kick. The trick to it seems to lie in finding outlets that differ enough from your normal patterns that you can recharge doing something that doesn’t feel like work anymore.
I would also add not getting enough sleep and exercise are big reasons for burnout. Each person is different so I can’t imagine it being a one size fits all cause and effect. If you are experiencing burnout here are a few resources that may help: