How to deal with exhaustion

Currently struggling to make ends meet living by myself. My roommate moved out and it's been a challenge to find a new roommate, but I need a roof over my head so I have no choice. I currently work a full time job where I'm on my feet 8 hours a day 5 days a week and pretty soon I'm going to be starting a server job for 2-3 days a week to keep myself afloat. Right now buying groceries is a bit challenging as I've only had my full time job and it only covers enough for me to be able to pay my rent and bills, so I have not had the best diet in a while. I eat pretty much once a day when I get home from work at 7:30pm because its all I can afford right now. The point is, I'm exhausted. My body already hurts tremendously from my first job and being on my feet all day. I am worried of whats to come with my new job. I just want my body to start feeling better. I want my body to hurt less I want my knees and feet to not feel like they're on fire every second of the day. Any tips on how to make the pain less painful? I've also been applying for desk jobs like medical reception but the job market is crazy bad rn.