UPDATE: Jen didn't get much better and I became more concerned with her crop, which had been looking persistently too full since I first noticed her illness. After some help and great advice from @casportpony , I decided to take her back to the vet and an xray revealed 6-8 tiny pellets in her stomach and one in her crop. We think these may have been lead pellets that spilled from inside a sandbag used to weigh down photography light stands. Yes, lead.
Her weight was down from 4.3 to 4.2 (her normal is around 5 lbs) lbs but her [peak blood count???] was up slightly from 10% to 14% though still scarily low--they usually start transfusions at this level but Jen's activity is okay so they won't right now and hope that it continues to climb.
Treatment is for lead toxicity which the vet says makes sense in regard to all her symptoms. She'll get an injection BID for five days with a medicine (don't know what) that binds to the metal. I'm paraphrasing, and possibly poorly. She'll stay on the Metronidazol to keep intestinal inflammation down.
I'm going to keep her at the vet for the course of the medicine where she'll be hydrated, medicated and retested. It's going to cost a fortune but I don't know that we can give her the shots and it would give me so much peace of mind that she'll have good supervision.
@casportpony --I did end up giving her that pill by mouth - you would have been proud of me.
Thanks for all the help guys and if you like I'll keep you updated.
Lisa