Another post reminded me of something.........everyone talks about NOT drinking the water on various islands....and most think NO WAY...I WOULDN'T.......BUT when we where in Cozumel last year at Carlo's & Charlies, I never thought twice about having a few margaritas...hmmmm ICE made from WATER....well we left there at 10:00PM and by 2:00 AM I was WIDE awake and on my way to the bathroom...stomach rollin' on the river..........WOW....but it was over in a short time.....BUT I never would have thought about it, but from now on I will. LIVE & LEARN. I felt like such a dope!!!!
Actually the water in Cozumel is quite safe and no reported problems. The water that C&C uses is clean water and this is not where your got your problem from. It could have been any number of places or things. The advice of not drinking local water still is a good idea in most places however.
Almost every tourist restaurant/bar in Mexico buys and uses ice made from purified water. And they also have filtered water. We eat and drink at many restaurants every trip and have been to Mexico maybe 10 times.Neither of us has ever gotten sick.