First of all, I am no doc, but if your doc says your Gallbladder has to come out and you also have pancreatitis, you need to get it out.
Your GB has already inflammed your pancreas, your gallstones could get worse and cause the following; Gallstone pain can cause vomiting, which may relieve some of the belly (abdominal) pain and pressure. Pain that occurs with a fever, nausea, and vomiting or loss of appetite may be a sign of inflammation or infection of the gallbladder (acute cholecystitis). You could get a blocked bile duct, and that is not good. Symptoms of a gallstone blocking the include: Yellowing of the skin and the white part of the eyes (jaundice), Dark urine, Light-colored stools, fever and chills.
This is something not to wait on. I would hate to see it progress into more problems.
The swollen ankles can come from the toxins in your body, or your meds, or just change in weather and humidity. There are so many things that could be causing it.
Please address the serious problems first!
I to have problems with my weight due to Hashimotto's Thyroid and meds. I feel horrible, I have days I am a bloated mess. I have put a ton of weight on due to predisone and my thyroid, I pound weight on like crazy and my ankles swell terrible and it is painful. I do the Lasix thing to and it helps.
Have him address the fluid retention thing after you take care of your gallbladder/pancreatitis problem. Get checked for gout, thyroid, etc. Discuss it with him.
I find that now, I drink lot's of water (check with doc on this) as the more I put in my body, the more my body releases, it decides it does not have to retain fluids, so it kind of flushes my system out. So with lot's of fluids and lasix I have a normal balance. But I am still heavy. This I am working on with diet and exercise.
I don't know if any of this helps you but please take care of the gb thing asap...