I'm soooo sorry to hear about your precious Belle. Vets just don't understand, we don't want to ever think about letting our babies go. I would trust in the people who replied and have been through this before, She will tell you when its time. My heart is aching for you and your family, I can't even get out what I want to say.........
Stay strong and hold her tight
You will be in my prayers......sending lots of ((((((((healing)))))))) vibes
XOXOXOXOXO from Doja