Im so sorry that your female yorkie is so sick. If she doen't seem to be improving I think is best to take her back to the vet. If your not happy with the vet you have , get a second opinion. If she is not eating it might be a good idea to give her some nutrical. Ask your doc to check her for pancreatitis, there have being some cases of that and some fatal. I will have you and your pup in my prayers. I hope she gets better soon. Please keep us posted.
Canine pancreatitis