i've been a vet tech for at least 5 years now and i have never seen a dog just faint. I'm so sorry, you must be so scared.
I do agree that she should go see an Internal Med vet. They have lots of experience with these types of things.
When you vet took a urine sample, did he do a urine culture or just a UA? maybe the bacteria in her urine is resistant to the ABs that she's been on? Or maybe its something else.
__________________ Kellie  and  Morgan |