Sorry you feel so low
I know how it feels when you think life will be so empty and miserable without drugs. before I went to detox for my benzo addiction I was so scared of how I would survive in life without them. But honestly, it's not as bad as you think. One thing that I learned is that life will definitely be worse if we are using. Even though the pills were taking my pain away and making me feel better for the moment, I was much more depressed in general. Try to remember that nothing will ever get better if we use.
I'm sorry to hear about your health conditions. It's just another obstacle to face, but try to at least read the stories on this forum.. there is a lot of support here.