I am sorry that it didn't work out for you! It has happen to me as well. I know that it hurts, it hurts bad. But what helped me is knowing that "pigpen" ( dog I gave away) is in a wonderful home and with a wonderful family that loves him, and he is the only fur-butt that they have so he gets all the love and attention. Then I think of Peanut being in a happier enviroment, not stressing on "pigpen" and being the only baby in the house.
I know yorkies love to be with other yorkies..Tons of yt's have 2 or more yorkies and it works great for them, but with some I think they only like to be number one. It's hard to find that special 2nd yorkie in a family that already has one yorkie that likes to be the only member...So my advice to you is that you know Hazel will find a great home, you don't have to worry about that. I guess be thankful you found out early that it wasn't going to work out.