My son got a stomach infection when he was about 2, he was throwing up all the time and diarrhea and couldn't eat or drink anything.. he even started pooping the white crystals which meant he was basically starving.
The doctors we went to in Strathmore were morons, they prescribed some gravol which was supposed to reduce the nausea, but that just made the diarrhea worse.
Eventually we took him to the children's hospital and they said that we were good to bring him in on time, they had to put him on IV and pretty strong meds. He was up and around in a day or so and home in another, but it was pretty scary.
What made it worse is some friends of ours were telling us about someone at their work who's kid had basically the same thing as ours (can't remember the name now), but they thought it was just a bad flu... they didn't take their kid into emergency though and eventually when he was totally unresponsive they called an ambulance but he ended up dying, they waited too long.
We were in and out of the hospital 3-4 times in the span of a week and a half (it's a bit of a blur), and I can't say enough good about the children's hospital, and I can't say enough bad about the doctors out in Strathmore, if I'd followed their instructions it may have killed my kid.