i usually read some fluffy bl like heesu in class 2. or go to yt and search for some clips of haikyuu. i watch more anime too. i cry when it's really worse. basically i just do more of the things i do during free time and that makes me forget why im burnt out in the first place which makes me pick myself up again
i listen to music and take a walk, and keep talking to myself during that walk. the process goes on for many hours, once to a total pf 5, that I got cramps the next day. the self talking helps reflect what went bad what could be done and what couldn't and then tell myself to learn from it move on. then I'll read something, (in such times I prefer reading novels over mangas) and try to forget about what happened.
cry it out, take your time, n then get back up, the pain never completely goes away but it does lessens.
best of luck
what do ya'll do to pick yourself up when you're super burnt out?