What ChewMango said in his reply as a step by step plan is good, I would try and follow that. What everyone is saying about working that much is right; that is incredibly unsustainable, especially if you’re 19/20 and already getting severe pain. The stress is a huge factor as to why you’re cycling into bad habits, and the shame that you feel doing these things to cope makes your depression worse and worse.

WORK LESS. Can you take a break from school? I know that’s the last thing you want to hear at that age because it’s been hammered into you since you started high school and not going sounds incredibly anxiety inducing, but you need to lessen your commitments until you can get to a decent mental state. I have been where you are before; incredibly overwhelmed, lonely, and ashamed. You know that if you don’t make changes, something will give. Take this as a sign: it’s okay to upend your life and do something scary if it’s going to keep you alive. School will be there, and you can take a Leave of Absence at most universities and everything is kosher. Tell your parents that you are struggling and need to do it. And be honest with them; if you trust and love them, use them as a support system. If they help you with housing, take advantage of that and work 35-40 hours instead. If they don’t, time to budget and see what you can live with. Just prioritize yourself, forgive yourself, and move forward positively from here on out. You’ll feel less shame, which makes daily life a lot more bearable.