Sounds like you're having a rough time of it, MTPetey. I currently deal with some of the same things you do. (Osteoarthritis in my left knee and foot, depression, etc.) I'm familiar with Tramadol and took it for a while until it stopped working. There are other exercises you can do that don't involve walking/running, etc. There are ones you can even do just sitting in a chair.
This forum is full of wonderful people with a lot of experience and knowledge. You won't be alone here. That's for sure.
Welcome to the the forum and best wishes for all your losses!!