Hi there. Welcome to YT
So sorry that your little one is not feeling very well. I don't know how to answer your questions, b/c I just don't know.
My Roxy who is 2.5 years old and weighs 5lbs didn't do so well with Clavamox. She was to be on it for 10 days b/c of a mild staph infection. By days 8, she had pure mucus poop, then followed by direaha and mucus. I still continued the meds for the next 2 days, but I later found out from the Vet that I should have stopped it ASAP. Roxy had mucus poop for 2 weeks after that!
All I can say is that do you feel comfortable with your Vet? If so then follow his lead, if not, then we need to find you another Vet asap. We are here for you, so if you need help, we will try to help you.
About the breeder. I would def. call and tell her that your pup is extremley sick and tell her how much money you have spent and go from there
