I'll see if I can help.
Did you breed her and it didn't take? Or is it possible she was bred by a neighbors dog accidently? How long has she not been eating?
First thing I would do is take her temperature and see if that's normal. If it's high, I would take her to a vet. If you bred her and it didn't take, it's possible there were puppies in the beginning, but they were reabsorbed. Or there's a puppy still in that's dead that won't come out.
As far as not eating, our girls don't eat a much the first few days after a litter is born, so we hand feed them because they have to eat in order to keep up with nursing. With you it's a different story; she doesn't have puppies to nurse. If she continues to not eat, I would hand feed her a small amount daily, but again take her to a vet to be sure everything is all right.
Ineresting thing, we had a girl that we bred and the ultrasound showed one puppy, but the vet thought it was in the process of being reabsorbed because it was so small. Sure enough, an x-ray the week before the due date showed nothing. However, right on what would have been her due date her milk came in. It happened that we had an 8 week old litter in the house that the mom had pretty much weaned. Well this girl decided those pups were hers and she started nursing them every chance she got. When they were out of the pen, she would just flop down on the floor in front of the pups and let them nurse. And when the pups were in their pen, she would lay on the floor next to the pen and growl at any dogs that came near the pen! After a couple weeks of discouraging her, she finally quit nursing the pups.