WOW - 6 weeks is very young to be taken from her Mommy and liter mates, actually 8 weeks is still very young too.
Most Yorkies stay with their Mommas until they are 12 weeks old, so you see, you still have a very, very, very young, practically new born baby. Unfortunately, the problems that you are experiencing are b/c she hasn't 'learned' all she needed to learn from her Mommy and she didn't get the adequate socialization from her Mommy and litermates. But what's done is done, you have her and love her to pieces. So with that said, it's gonna take time, go slow and be patient with her, she is a new baby, she needs to be trained and loved, she'll come around, she needs to just grow up and see a little bit
