Persistent cough and now projectile vomiting in 8 month old

[renegadesoundwave]

DD has had a nasty cough for the last three weeks: was initially diagnosed as a chest infection, she was given antibiotics and seemed to respond well, while the cough persisted she still had a good appetite and was pretty lively after 48 hours.
For the last three days she has been listless and unable to stop coughing at night. We had two days of projectile vomiting (she's really not a pukey baby normally) and took her to the doctor.

The GP's diagnosis seemed to be 'she's a baby, they get sick, she hasn't got a chest infection, give her plenty of water and don't worry about it'. I thought she was on the mend yesterday as she seemed to be able to keep very mild food down; however at night she couldn't stop coughing and eventually was forcefully sick. She seems chipper enough this morning but the cough is really awful at night.

DH thinks I'm being completely paranoid and she's fine ; I can't think that three days of projectile vomiting is normal. Have tried nasal aspirators, Karvol, humidifiers and so on which seem to help temporarily, but is it worth my going back to the doctor if the vomiting persists?

Vomiting is not a big issue unless it is related to a bowel obstruction. If she has no tummy pain, is passing wind and/or having dirty nappies I would look to dehydration being the issue here. Give plenty of fluids, smaller amounts and more frequently. Is she having regular wet nappies, is she alert?. No blood or mucus in the vomit obviously.
If becoming dry nappy wise and lethargic then she would need seeing otherwise it is self care.

Does she have fever?