Burnout is not a four letter word
I haven't met anyone who hasn't faced burnout in their career in the arts, and it's ok. It's hard and it's not fun, but you can get past it. You just need to find ways through. These are some things that help me:
Have a hobby/ do things that aren't related to theatre (or, at times, even anything artistic). I'll paint or crochet, watch crashcourse videos, go to karaoke, or watch my friend's wrestling matches; Something that isn't related to theatre. Don't even listen to a musical soundtrack. Jam to Fleetwood Mac, Lizzo, or Chance the Rapper, but any OBC is off limits.
If you can, take a break. Theatre is a fun job, but it's still a JOB, and you need time off to recoup. I got a job at a bookstore and didn't work any theatre jobs for 3 months. For some people it's their source of income or if you stop accepting jobs you lose your credibility in town (which is a whole other beast), but if you can find a way to take a week off between shows and go visit your sister out of town or road trip to an Airbnb by a lake, or even if you can spend a week vegging out in your apartment and playing board games with friends, do. Sometimes the best cure for burnout is space
Along similar lines, your time off the clock is off the clock. If it isn't crunch time before a show, have time every night set aside for not theatre thoughts. Unless it's tech week or my director tells me they'll need me early or late on an off-day, I will take time off outside of rehearsal times. I won't be available after 10:00pm or an hour after rehearsal, whichever comes later (if rehearsal gets out at 9:30, I'll be available until 10:30), and I won't let myself work on the show after 11:30 pm or before 9:00 am. Boundaries are good, even if they're hard to set.
Get on a regular sleep schedule. A long night of rest isn't a privilege everyone has, but even if you can't sleep long or often, try to fall asleep at the same time. It's proven to not only help you sleep better and feel more rested, but it also helps with cognition, mood regulation, physical health, stress reaction, and a whole bunch of other things
If you can afford it, get a therapist. I'm a firm believer that everyone should have a therapist, regardless of mental health. For realsies, get a therapist. It's life changing.
These are things that I do when I face burnout, but the biggest thing I've learned is that burnout is real. You aren't being whiny and complacent because you don't feel inspired and/or fulfilled by this work right now. It's something most if not all people face, and you aren't broken or wrong for feeling this way. Reach out and let someone know what you're feeling and they may be able to help you. You can get through it ❤️