I wonder why you weren't told at the time about the signs of swollen gallbladder wall. This indicates that your gallbladder is very full and isn't emptying and filling properly. The condition known as biliary stasis is the cause of much discomfort. The intense pain is usually pancreatitis where the biliary dict is obstructed as material passes down it. Both stones, sludge and thickened bile can cause this. The duller gnawing pain can be gallbladder pain.
The word disease used by you doctor can be misleading because it is used to describe the gallbladder which may be rather full of stones but otherwise in good order. If it has infection then this shows itself in the blood works and other low fever like symptoms.
As you continue to flush you may suffer as the gallbladder starts to operate again. I wish you well.
PS. Isn't it interesting that a doctor dismisses a condition because it is rare! I do agree that it is very rare.