MY dog- Snow and her Pup

Ok here it is. My friend said she knew a dog that needed a home or
they were going to take her to a shelter, I said I would take her.
The
first thing I did was take her to the vet. Of course she was
pregnant.
None of this was good news. She is a Pom, weighted 3 pounds, had
experienced Parvo, and was due in about a week. So aborting the pup
wasn't really an option. The vet was able to tell me there was 1 pup,
we started her on vitamins and prescription dogfood to try to bring
her up to health. C-section was a very likely (but luckily the
previous owner knew that it was a pom that got her pregnant). So we
have been to the vet four times in 3 weeks. First when she was
whelping, as we wanted to make sure she didn't become distressed,
once
3 days later to make sure mom and pup were ok and have the dew claws
removed, and once when the pup turned 2 weeks old, we go back in 2
more weeks. The problem is I have never had a dog that had pups and I
have read and read, but don't know how to tell if she is out of milk.
The puppy has been very healthy so far, and was a good weight 3 days
ago, but for the past 4 hours it seems the pup has tried to nurse,
but
it's whining and I am scared. My vet will be in, in 4 more hours, but
I wanted to know if anybody could help me before then.
Yes, SHE WILL BE SPAYED as soon as possible, but the vet avised me to
wait till she is done nursing. I have grown to love both her and her
pup and am very scared, so if anybody out there can help me I would
greatly appreciate it. I do have esbilac, just in case she runs out
of
milk. Her and her pup are in the whelping crate that my vet helped me
prepare, she is still tending to the pups needs but it seems like she
is pushing the pup off when the pup tries to nurse