Hello and welcome to YT!!!!!!!!! I am sure a breeder will help you with your breeding questions. I am so sorry about your first litter. It is for sure that your yorkie trusts you and loves you, that is why she brought her last baby to sleep with you, at least that's what I believe. And don't think you did anything wrong........we all learn from all our experiences in this life.......if things went perfect every time we would learn nothing.
I'm sure you will find Yorkie Talk informative, and the members very gracious.
Again, Welcome