I understand your plight, as Dirty Hammer almost had the same thing happen to her, but fortunately she did not lose her uterus--but she too was sick with a uterus infection while pregnant and needed a c-section.

My vet prescribed Clavamox and metronidazole and it cleared up, and it sounds to me like you're doing everything you can, especially with the addition of LR which can only aid in hydration (although simple saline might be the better choice).

Additionally, I am a firm believer that adding a horn of garlic (freshly-blended in a cup of water) to the feed will only help combat any overall malaise in a dog.

Jack