I'm saying this as someone who went to law school while my husband was in grad school, and watched a friend go through law school while his wife was in med school: our lives were not like you're describing. We all did very well in our respective schools, but none of us had a joyless two-four years of misery. There is some way you can make this a little better for now, I promise. I mean, even swapping some gym time out for another free sport you enjoy more could help. But I think you could most benefit from examining how much you study and maybe cutting back a bit. I remember the 24/7 study people and frankly they did worse or burned out completely across all three fields. It sounds like you're headed there.

I know your first response will be "I can't study less," but please don't stop at that. Take two weeks and carve out some amount of additional free time. Don't use it to be a responsible adult. Then genuinely take stock of how that affect to your school work. Two weeks of, say, two less hours of studying won't tank your grade, and if it is actually heading there you can go back to studying all the time. Just be really honest about the effects on your work and mental health.