You'd think I'd know by know, but this is the first time we've had this. Tom (18 months) vomitted yesterday morning but was then fine all day. Then he vomitted twice this morning, is totally off his food (ie hasn't eaten anything and he is usually a very big eater) and seems to have a sore tummy, be out of sorts and have a slight temp. He seems to be keeping enough bm and water down to not be dehydrated. Should I be worried?