I’ve had chronic diarrhea for two years since I had hip replacement?

I’ve had chronic diarrhea for two years since I had hip replacement, started right after I stopped the pain meds. Also took alot of Advil etc before surgery from so much pain. I’ve had C-Diff test, parisite test, colona guard . I’ve done the brat diet, fodmap diet, no grains, no dairy, stopped nascort, stopped benadryl, I take only levothyroxine 100MCG, Colon probio. I really believe I need to heal my colon

Age: 61
Female
Medications: levothyroxine