I just went through exactly what you are going through. Here is a link describing what happened with Gizmo
http://www.yorkietalk.com/forums/gen...r-bedtime.html , the good news is he's doing amazing right now.
The girl that was selling Gizmo also was trying to sell him as a micro yorkie. I talked to the vet, as that is the first place I took him, because when I first seen him I could tell he was extremely sick, and had to get him from the girl just to have him treated.
The vet told me, there is no such thing as a teacup or micro yorkie, and some very bad breeders will actually feed them a very limited amount of food to stunt their growth, to make them tiny. It's all really very sad and horrible, and I cannot even imagine what these people are doing and how they can even sleep at night.
I also got a rx wet food fr critical care puppies, that he ate really well once he started coming around, maybe your vet might carry it? I had to spoon feed him every hour fr the first 36 hours, till he finally started coming around and the whiteness started to go away from his gums.
I don't have that many posts here, but if you go to my profile, then to statistics, you can read all of my posts and get an idea of what I went through for the last almost 3 weeks. I hope it will help and give you some good ideas, as the help I found here was invaluable to me and Gizmo :-)
He is truly one amazing loving little healthy puppy now, and his weight now is right on schedule :-) I can't feel all his bones anymore and am just so happy I found this forum :-)