DS 21 months has my cold. Lots of coughing, temperature controlled with calpol and nurafen, really miserable, vomited 3 times yesterday. Not really eating: today has eaten small piece of crust of toast, one (!) pea and 2/4 of a ginger nut biscuit. None of this worries me, as he'll survive a few days like that. But I really cannot get him to drink much, and his nappies have been pretty dry. He has 2oz of milk tonight, and a few sips of water during today. I have offered him his favourite juice, smoothies and ribena (which is strictly taboo in my house, me being a dentist). And of course water. Not interested. He's currently sleeping (though a bit restless). Any ideas? When should I start getting worried?