water fasting inducing kidney stone passage?

hey fasters,
i just endured my first experience with passing a kidney stone this weekend...not too fun. coincidentally, i also just finished a 14 day Water Fast (this is my third fast this year, and my longest ever). since I didn't know what was happening for sure, i went to the ER for this and the ER doc believed the fasting had nothing to do with the stone passing...i'm not too sure i buy that 100%.
I've been hunting around the kidney stone forum and so far, it seems maybe not being hydrated enough may have brought this on? maybe I didn't take in enough water in my most recent fast? I am really curious if anyone else who regularly Water Fasts has ever dealt with this issue...
thanks, kozzz