I just checked your location. My suggestion is to go to Michigan State Small Animal Clinic.
Small Animal Clinic | College of Veterinary Medicine at MSU
This illness can be controlled,but if your vet is not familiar, I would get to a specialist and they look to be the closest to you. When these pups start having fluid in their bellies, it is pretty serious. It would be best to have a specialist take a look. She definitely should be on prednisone, but perhaps other meds as well....
Is she eating? It is really important for them to eat; and yes, she should be on very low fat.