You have been through a lot. Grieving takes time. You have options for your future.

A lot of us will work until we die or work well into old age. I personally think it's the way it should be. No one should ever stop being productive. Do you like your work? If you do find the aspects that are most enjoyable and become the expert. If you don't like your work start exploring what you would like to do. If it's something that seems out of reach be creative and think about how you could support that type of work

You physical well being should be everyone's #1 priority. Are your knees candidates for replacement or rehab? I let an arthritic knee go for 10 years. That was not a wise decision. It created more health problems. Make you the # 1 priority. When you feel better your life will be better. Age is just a number.