I can relate
We had our Yorkie Bailey spayed about 4 weeks ago she was 7 months old she only weighs 2.2 pounds. The vet said had she not been at 2 pounds she could not have had the surgery. She also had 6 baby teeth removed because her adult teeth was trying to come in around them. She was about 3-4 days laying around. She had to wear a cone because by the next day she wanted to lick it so make sure you watch for that. I spoke to the breeder that I got her from the week before the surgery and she told me that one of her friends had a yorkie spayed at 6 months and she weight 2 1/2 pounds and she had a hernia removed also and that she did just fine. I know it is scary but when they are so tiny I feel it best to spay them because I feel that having pups would be so hard on them and they may end up having to be put to sleep if they are to small to birth pups. You are doing the right thing