This happens to me regularly. Any time we have a long-running project, or I end up on something with a lot of sucky work for a while, I feel at least modernly b

This happens to me regularly. Any time we have a long-running project, or I end up on something with a lot of sucky work for a while, I feel at least modernly burned out at the end. There have been other times in my career where I was a lot more than moderately burned out. And all of this while working basically 9-5 my career. Never 100 hour weeks. For me, the minimum is to take some time off. Get away from the drudgery and have some time to think about other things. If it's bigger than just a need for a vacation, I'd echo the other comments here to try to find someone to talk to about it. Have someone talk through it with you, especially without having an agenda, can be extraordinarily helpful.