poor you This happened to me at 37 weeks. What I was told was that the lack of food would not be a problem, as long as it didn't go on for too long, but that dehydration could be dangerous. So I would keep trying to sip diaraloyte or equivalent, and ring your GP or midwife for further advice about avoiding dehydration.
I had noro virus at 27 weeks. Was completely unable to keep water down and after 24 hours the midwife came and gave me an anti sickness injection that really helped. If you are able to keep down water don't worry too much as a couple of days without food won't harm the baby.