I may be wrong, but I think 53 days IS due date. I don't believe vomiting is part of the labor process, so put in a call to your vet for advice. That will at least put him (or her) on notice that there may be a problem delivery coming his way. Why do these things always happen on a weekend?!
Any vet clinic should have an outgoing recording telling you what to do or where to go in an emergency. This situation qualifies. First get some advice over the phone, and then you'll know what to do as labor progresses if things get dicey. It's always best to be prepared for the worst.
Please post back and let us know how the birth goes. :-)
We are still waiting for the puppies to be born her temp has droped from 100.4 to 99.6 so it is a matter of hours till those little babies are born and we can't wait will keep you posted. Thank you for post on my question.
Heather