Wish I could help but I don't know alot myself. Maybe by morning a most experienced yorkie mom will respond. You might post what type of diet your using even tho vet recommended it. I've read here that some owners will use baby food (chicken & rice). Go to the Health & Diet thread & see if helps answer your question. I think it's great you adopted.
Since she's soooo little you really should keep some nutri-cal or karo syrup on hand for emg. Its to treat hypoglycemia (low blood sugar). Please type hypoglycemia in your search engine & read up on it. It usually occurs in the first year of the pups life. But can happen to adult dogs, too. You might try
www.yorkiepassion.com/yorkiepuppyhypoglycemia.htm
Good luck. Thinking of you & your tiny one. Please post updates.