Since 1/1/21 I have lost 42 pounds. I do not exercise because of a severe hernia.. hernia surgery scheduled for 5 16 22

I am in the same situation. Every month when I went to get my infusion I would gain another 5 pounds. I complained to my doctor and asked why. He said " I'm sorry it's because of my sedentary life style and the medication. Sooooo I go from having RA to all these issues caused by treatment. Exasterbating all of the issues RA causes. How can I fix it ! Eating an entirely plant based diet and exercise. Can I do either one of those? No I can't.