The other thing that came to mind is called the "Dog show Crud'. Actually many times it turns out to be Camphylo Bacter (geez I didn't spell in right) It is highly contageous from humansto dogs and back. AND dogs are still carriers unless they've been on a course of Antibiotics. For whatever reason vets don't seem to catch this one.
Syptoms sound about the same - don't eat, vomit, loose, very loose and bloddy stools, lethargic. etc.
It's good that she's on antibiotics. When you start feeding her again - add some yougurt or something bland to help her tummy.
Good luck - and keep us posted.