I really feel sorry.
Our dog was this close to death. We thought he had a cancerous tumor, and the vet had 2% hope in him living. We all cried, and Sammy (the dog) has been in our family for a long, LONG time. The tumor turned out to be a bite from a poisonous spider after the doctors tried to get the tiny tumor out of Sammy. And thank Jesus the docs got medicine to prevent Sammy's death. But Sammy is very old, but energetic. He could die in the next 1 or 2 years or so.
But I really do feel sorry. We had 2 dogs once, but one died of old age at age 14 or so when I was a baby. Damn, I can't remember all that. I don't remember any birthday parties before my fifth. But, I feel sorry. I've experienced pet death, but I was a baby.
tl;dr: I know that feel bro. Sorry for the loss.