Stuck in a Vicious Cycle of Health and Mental Health

i feel like I'm stuck in a vicious cycle. My physical health gets worse and I put all of my effort and energy onto getting better. Then, when my physical health has stabilized, my mental health completly tanks out of sheer exhaustion. I feel miserable and lonely and useless. Sometimes I manage to drag myself out and have a few good days before my health finds a new way to fail, but most of the time I just have no choice but to pull myself together so I can keep myself from death. I'm so tired.