He woke up Thursday night with vomiting/diarrhoea. No subsequent vomiting but more diarrhoea than I've ever come across, but only really in the mornings (so we're talking 7+ episodes pre-midday Fri, Sat and Sunday, then it settles down a bit). In the evenings he's been having horrendous wind/stomach gurgles.
None of the rest of us are remotely affected, which is making me think it's not a Norovirus type thing - although not food poisoning either, I don't think. And he's relatively OK in himself - I'm making sure he's not dehydrated - and he's quite cheery. He's eating - not much, but something.
He's 15 and has recently been diagnosed as anaemic, if that's relevant (is on iron, but has been for a couple of months so I don't think the iron's the problem).
At what point do I see a GP? And any armchair diagnosis would be very welcome.