I know this is a very common problem - I'm not at all unique in this. And any advice I give to deal with burnout best relates to my specific situation (university math teacher, married to another teacher at the same university, no children yet). But hopefully, even though these tips will probably be very specific to me, there is still some helpful advice if you're feeling as burned out as I am!
1. Learn to say no.
Every now and then, I have to remind myself I'm not obligated to do everything my students ask me. It's okay to take time for lunch. If they ask for extra resources, I don't have to drop everything and do it right away. If they wait until the last minute to get their homework done, I don't have to see them on a Friday afternoon, after individually meeting with a half dozen other students already. Whenever I've been able to trim my schedule to the bare minimum, I've been shocked by the amount of work I'm able to get done at school! Trying to minimize extra commitments, as much as is feasible, has been really helpful in reducing my burnout.
2. Pick one fun thing to do each week.
3. Increase productivity by budgeting your time.
The biggest killer of productivity is if you hop around different tasks. I have the issue where I'll be working on something for one class, and then remember something else I need to do, and then get distracted by a sudden influx of emails, and then have a meeting with a student, and then by the end of four hours I'm not halfway done with the first task. I have found that if I group my tasks into segments I am much more productive: I try to make sure that I leave my emails alone for the time that I need to prep for class. If I'm trying to finish material for one class, I'll make sure I finish that class before I move on to the next. The more my time is focused, the more productive I am for each segment of my work.
4. Do the unpleasant work first.
So I started trying something a little different recently. During the week, when I have to do the usual daily grind stuff anyway, I do all of the work I enjoy the least. When the weekend comes around, I'm free to do the work I enjoy more. So my weekends are more devoted to my rest, while the week is full of work as it would have been anyway. Actually being able to enjoy the weekends helps me start the week with a fresh mindset.
5. Avoid the "I'll rest later" mentality.
So what I've tried now is to budget a little time for rest. The work will still be there when I get back to it, of course. But at least I'll be a little less burned out when I start again.