DS2 (age 9)has been vomtiing since 10pm

[Saltire]

He came downstairs at about 8 and said his tummy was sore, I told him to go back to bed. Then I heard him at 10 being sick, really sick. Then it just hasn't seemed to stop. he's at the stage now where its mostly retching, and if I give him a sip of water, it comes back up again within 5 minutes. He has also ahd bad diahorrea. We are both shattered. 3rd night running for me with no sleep.
At what point in the day should I start trying him with water again? He's fast asleep now! I don't know what's caused it, as he was fine during the day and he and his brother ahd the same thing for dinner and he's fine

Let him sleep as long as possible, but when he's awake keep offering water to avoid dehydration, even if not much stays down. These things tend to be short and sharp.

I feel bad because he tends to complain on a Sunday night about tummy ache, because it's school the next day!
He had 2 teaspoons of water at 7.15am, which he promptly brought back up again!
I need my bed too, as he was in with me because he was being so sick and I've not slept a wink

My dd's been sick since Saturday morning so I can really sympathise. Sounds like the same hing - sore tum and really violent sickness, although she hasn't had diahorrea. She doesn't want to eat anything this morning - just water - and is just flopping on the sofa.

Doctor on Saturday said it was viral and could last quite a few days. There's a bug doing the rounds apparently (we're in N London) if that helps.

Flat coke, or lemonade as Herbie suggests. Another possibility is crushed ice - sometimes this stays down longer than water. Literally a teaspoon, then wait and see....good luck.

He has managed to keep some water down, I've been giving him sips of it since 8am, and he had 1/2 a slice of toast. he says his tummy is really sore and is walking to and from toilet bent over and is lying under the duvet bent over as well. Would calpolo help at all? He has had some flat lemonade as well

Hot water bottle and or warm bath might help the sore tummy - I expect that's muscular from the physical effort of being sick. Not sure yet about Calpol, my DC's always recycled that, more so than water. Do you have an electric blanket - that can be quite soothing on a low setting for a while. I should think you are out of the worst of it, probably by tomorrow he'll be feeling heaps better.