How do you deal with burnout and stress from being overworked?

Not to ignite a whole "Teachers vs everyone else" debate, but I'm not sure you're going to get a whole lot of sympathy from people because you "only" finish work at 5pm the odd day. My work hours are 9 to 5.30 (was 8.30 to 5.30 in my last place) and I often end up working far later than that - I didn't log off til after 10pm last night, for example, and we don't get paid overtime. It's the nature of my industry and I'm happy to do it, for now. If that ever changes then I'll look to move on. You may end up having to do the same thing, although I'd counsel you to be very aware of the kind of hours you'll end up doing 5 days a week (every week, all year round) should you decide to leave the profession.

No one in this world can force you to work at something you don’t want to work at. If you’re not happy in your role or feel you are being over worked then hand in your notice, quit your job and take up a job in another role that will suit you or the hours you’re willing to work better. It’s that simple really.

But as @Dial Hard alluded to above, be careful what you wish for. There’s not too many jobs out there where you only have to work until 5 an odd few days, 5 would be a fairly standard quitting time for a lot of office based roles as well as construction and plenty of other sectors. Generally there’s no early Friday finish in the majority of jobs either so I’d advise you to do some research into the job you’d like to change too and what the financial difference would be relative to where you are now if you only want to work half days.