I agree. I would definitely go over all supplements with a dr. Especially since you're taking water pills, ordinarily for high blood pressure, to lower calcium.
Honestly, that's one's a mystery. Did the dr prescribe the water pills? I had to be on them too but only after my calcium got dangerously high (I mean, as in, hospital stay high). It was only temporary since it's not the best idea for high calcium but, apparently, will work if relief is needed fast. I remember being ordered to get off them because of the kidneys. I honestly can't remember why but do know the pills were not to be an ongoing treatment. Only surgery to remove the bad parathyoid gland was a resolution.
Only speaking this because I care...
I have little experience with potassium citrate but I do know it may help with your symptoms on low calcium.
Both these supplements can become toxic in the body if taken in large quanities.This would definately be a good question to speak with your doctor on.