Oh, dear, she is so young to be away from her mommie and a schedule she is familiar with. Likely she is scared, worried where her mom and such are, feeling strange and trying to get her bearings. I am no real help as it's been since '91 since I had a puppy and she was 4 1/2 months old when I got her. But I would search threads here on hypoglycemia and read the Puppy Care Guide in the YorkieTalk Library for all you can learn.
Just until someone comes on who can help, do you have Nutrical or some local honey or karo syrup you could put on her gums so she can get some glucose and syringe in some water every 2 hours using a needless syringe until you read or hear more from someone who can really help you?
Maybe if you Google the term hypoglycemia and Yorkietalk you will pull up the threads quicker and be able to read better answer than I can give. It is good to have all of this information before you shop for a dog so that you are prepared for every single possible thing that could cause them trouble. If she is lethargic and won't respond much and such she very well could be hypglycemic. You might need to get her to an Emergency Vet if anything like that starts and check on her overnight to be sure she will arouse and act alert and keep putting some nutrition in her mouth.
Maybe even just mixing some of her food with water and a little karo syrup or honey will help her. I wish I knew more. I will post that link to the Puppy Care threads in just a moment in another post.
__________________  Jeanie and Tibbe One must do the best one can. You may get some marks for a very imperfect answer: you will certainly get none for leaving the question alone. C. S. Lewis |