Hi Lucy -
I don't have anywhere near the problems you have, but I do have a rotten back, fibromyalgia, GERD (operated, but needing a re-do), bowel problems not labeled yet but possibly due to fibro and loss of nerves due to polio.
Every time I end up in the hospital: stomach surgery, knee and hand surgery, diverticulitis, ... I come out on pain meds and it takes a month or two to feel well enough to wean off. I actually end up feeling better off the meds!
Same for the fibro drugs. I've tried everything my pain doc has suggested, and I feel better off all of them - except for tramadol.
You want to get off your meds, so you will probably wean yourself off over time, and I'll bet you will feel better too. I expect, like me, you'll still need something for the fibro, but it would not be surprising if you feel better without the antidepressants. Those never made me feel less depressed! But off them, I only feel depressed when I'm hurting. As soon as the tramadol kicks in my mood lightens too.