I would tend to have a different opinion than your doc about the fluid retention & diuretics. My daughter is on a mild diuretic because her transplant meds cause her blood pressure to go up due to kidney damage from the immune suppression medication. The diuretic lowers her blood pressure & is preserving her remaining kidney function. Diuretics come in all sizes - but if the swelling is caused by the steroids (likely) just throwing more pills at you isn't the answer either.
I just read the book "The Plant Paradox" which puts forth an intriguing theory about the way we eat as vegetarians. I'm a pescatarian but in my day to day diet - nearly all my calories come from plant sources. I'll order fish if I go out if the vegetarian dishes look kinda ify. The MD who wrote this book made a lot of claims about this diet helping his patients overcome inflammatory & auto immune diseases. I read it to incorporate some of its principles into my diet to try to help my asthma.
I'm so sorry you're still struggling to regain your health. Please know you are in my heart. <3