Congrats on your new addition! As bad as I hate to say this, but I would probably report the person you got the pup from.
8 litters and she is 6 years old.
When I got Mikki she was over a year old. The first few days she was the calmest thing you ever seen. She was scared and in a new environment. Lets just say she has gotten over that fear!
She now plays and plays and plays! Maybe a few more days will help.
As far as food goes, I home cook for mine. But I feed Blue Buffalo as "snack" food. I do use the sensitive tummy formula because some Yorkies do have this problem.
Good luck to you and can't wait to see pictures!