He's had a cough and a snotty nose for about a week or so, so i took him to the gp on Monday, where a med student checked him out, and said he was fine. then today, after 2 sleepless nights and a bout of vomiting i took him back to see the nurse practitioner who listened to his chest again and shrugged at me. she said she's seen a lot of this at the moment, but it's not a virus or anything, so it can't be treated. he's now vomiting after every milk feed, refusing all solids (even yoghurt, which is most unlike him!) and very lethargic. what do i do???