I'm sorry your baby is sick
I highly recommend another vet. I lost my precious Starr to a less than stellar vet, and it damn near killed me knowing that I could have saved her if I had just gotten a second opinion. She hgad lost almost a whole pound (she weighed 5 lbs normally) and didn't act agressively enough to save her.
Antibiotics are not going to help her at this point, matter of fact they kill all of the GOOD bacteria in the digestive tract and will just contribute to stomach upset, which can make them stop eating. See if you can get her to eat some plain full-fat yogurt with live cultures to start up her digestive system again. I wouldn't recommened feeding her so much cheese too, they can't handle all the fat.
Get a recommendation from a Yorkie breeder in your area for another vet, one that KNOWS how important it is to get to the bottom of these little ones' issues. A tiny dog cannot afford to lose too much weight
.
Good luck, I hope that she feels better soon
!