Oh you poor thing! That sounds awful!

This is a long shot, but worked for DS recently when he had gastro...

Try having a tiny sip of flat cocacola every two minutes for 15 minutes. The cocacola has to be really flat, my GP's tip was to mix a teaspoon of sugar into it (it makes it sickly sweet) and that makes it flat right away. According to my GP it works wonders in terms of settling the stomach.

HTH