My Mia was just about 3 pounds when she had her spay. She was just over 6 months old.
Have your vet run a blood test. Its worth the extra money. (I think it was $60 at my office) I'm pretty sure the reason for the blood test is to make sure your baby won't have a reaction to anything. Someone please correct me if im wrong!!
I was a nervous wreck as well!! Took Mia home the same day as her surgery and by the next morning she was just fine.
I'm very sorry for the loss of your daughter.....