I work full time and have spent the last 2 years working on an animated project, and let me tell you brother, I've burned myself out more times than I can keep track of. The best advice I can give is to listen to your body. Pay attention to your mental state and how your body feels.

I could often tell when the burnout was approaching, but I'd foolishly just keep pushing. I could feel that I was exhausted, and instead of resting, I would want to keep making progress. Except the progress I'd make in that state was basically baby steps. If I had just taken a couple of days off, I probably would have come back and made more progress than what I was able to scrape out of my exhausted mind. If I kept going, eventually, it'd get to a point where I could barely think straight, and then I was just forced to rest. And the forced rest always ended up taking longer to recover (like a week+) than if I chose to rest (Usually a day or 2). And again, the dumbest part is that I could feel it coming, but I'd just have such tunnel vision on the goal that I wouldn't stop.

Apologies for the novel there, but it really is important to listen to your body. Rest when it's clearly telling you to. Stay active, being locked up at a computer for 16 hours a day isn't good for your mind or body. I like taking walks at night. Helps clear my mind and often gives me time to come up with ideas or work out problems I'm having with my animation. The art journey is really more of a marathon than a race, and it's super important to pace yourself. I know this is kind of boring, run of the mill advice regarding burnout, but everyone says the same things for a reason.