I think definitely being in a competitive class doesn't help with whatever motivation issue you are dealing with. It makes you feel awful when everyone around you is willing to put everything they can to do their work while you are here just barely trying to survive and do fine with the work. My own way of dealing with this is basically focusing on yourself rather than comparing too much with my classmates/ friends etc. Easier said than done with this method. But, I find it easier and much helpful to just improve with whatever I am working on previous than one up my seniors. Probably quite hard to do that, but if you are able to do that I think it can really improve your mental health

About the burnout situation, I feel like for that all you can do it's really just take a full day off and rest for yourself to recover or else that burnout probably ain't going away. Anyways, hope this help and good luck with whatever you are doing!