oh how my heart aches for you right now! I know exactly what you are feeling, as I lost my beloved little Coco last June while under anesthesia. I still have not gotten over it and think perhaps I never will.
I chose not to spay her younger sister (who was scheduled to go in a week after I lost Coco) and also not to spay our newer puppy. Mine are 2 1/2 & almost 4 lbs.