Keep breastfeeding, I think, if she'll take it. And if not, then the tiny sips recommended. Sometimes we've found that there's just too much stuff (water, whatever) in his stomach for him to process and up it all comes. There are also anti-emetic suppositories which have been very helpful for my son. Don't know the name, sorry, but if you're still worried (and I hope she's getting better!) maybe ask your gp.