I am so sorry you're in such pain, physically and psychologically. Are you seeing a therapist you can trust and be open about these thoughts to? Being sick isn't your fault, and your worth is not determined by what you can produce--these are lies cooked up by am ableist society and your depressed brain. If you can't talk to your therapist about this I think finding one needs to be a priority for you. Please, please tell people in your life that you are seriously depressed and need help. No one deserves to suffer as you are suffering.