Okay... I've read this entire thread and I can't keep my mouth shut
First of all, it is not fair to say the OP holds blame for the pup being sick. The OP holds blame for buying the pup from a red flag flaring breeder/broker/whatever the heck she is, that I do agree with. She should have never bought her. HOWEVER, the OP holds NO blame in my opinion for the sick pup.
The pup should NOT have been released by the breeder sick. Period, end of story. I can honestly say from what I've gathered any breeder with merit would never release a sick pup... they would hold it until it was well. The impression was given that the pup was better and the drugs sent home were a safety net of sorts. I probably would have taken the pup home too if I trusted that person. I would have assumed that they saw the vet again and this is what the vet said, because a responsible person would have taken them to the vet AGAIN if they were still sick.
Moving right along. I do not think the OP should be blamed for the vaccine mix up either. She is not a vet and deferred to someone she felt was more knowledgeable. There is NO shame in listening to a vet when you don't know the answers. It isn't fair to ask her to disregard medical advice when she isn't researched on the topic and especially hadn't encountered the situation before. She was worried about the pup and rushed it to the vet. Any of us would have done the same.
Sure a lot of you know better about vaccines and such, but guess what? Not everyone knows as much as you. Some of us have to rely on our vets for advice when we don't know what to do, especially in a situation with a new pup that we're worried about. We defer to professionals because they supposedly know better than us. In this case, maybe the vet didn't, but I don't think it is fair to blame the OP. For this aspect, I would blame the vet if anyone.
Therefore, NO blame for the pup's illness should reside with the OP. Most of it should be assigned to the breeder because if she had not released a sick pup in the first place NONE of this would have happened or if she DID release a sick pup she should have given SPECIFIC instructions on what to do and what not to do with the pup (e.g. educate the buyer about the vaccines since you as the breeder should know better). Thus, in my opinion the breeder is most at fault here. The vet is secondarily at fault by making a poor judgment call as a professional. The only thing the OP can be accused of is trying to take care of her sick pup.
To the OP: I'm so sorry you're having to go through this and I'm sorry you're receiving so much flack (from a secondary source no less). I hope your baby is feeling 100% better soon. Hugs to you and her.