Despite my age, I've only had one dog from puppy to passing. She was only 9 when she was diagnosed with pancreatic cancer. We paid extra to have the Vet do the deed at home and I held her and talked to her the whole process. She literally died in my arms while I told her what a good girl she was with tears on my face.
We got a new dog a few months later, another female, and I still, almost 6 years later, can't call her my good girl because in my heart that title is reserved for my first companion. Instead, I call her my good puppy.
All this to say that I understand and am sorry for your loss. Dogs enhance our lives like no other animal can.
