Ness, I am in the same boat as you with my DS (also 11 months). Sorry about this long post, but just wondering if someone could advise.
2 days ago, he couldn't keep any food or formula down. He'd vomit about after eating or drinking formula (anything from 5 mins to half an hour afterwards). He could keep water down ok though. I gave him beakers of water mixed with Dioralyte (rehydration powder) after speaking with the local pharmacist, and did not give him food or formula for the rest of the day. He was fine - no more vomiting.
Yesterday he didn't vomit all day. I continued giving him water & Dioralyte, and gradually introduced a bit of toast, which he kept down ok. Then tried a bit of pasta & tuna, which he also kept down. I noticed his poos were a bit runnier than normal, but I reckoned this was cos he was mainly drinking fluids, and not eating much solid food. I gave him his afternoon formula, which he kept down ok. Then, as he seemed back to normal, I gave him food at teatime, and his formula at bedtime.
Today he has been eating & drinking as normal, but his poos are still runny. He normally has 2 or 3 a day, but today he's had about 6 and they've leaked a bit out of his nappy - yuk. Then, just as I was going to give him his tea, he vomited everywhere. So now we're back to square one with water & Dioralyte .
Is this normal or should I be worried? I spoke to the health visitor 2 days ago and she said don't worry as long as he is keeping water down, but if it continues I should see the GP. At what point should I see the GP?
DS is still his usual cheery self, doesn't have a temperature, and is still sleeping well at night. He just has intermittent episodes of being sick, and has runny poos. What do you reckon? Tummy bug? Ride it out for a couple more days?