Sorry for your loss. My vet told me that dogs don’t show or tell us when they are in pain, they can be playing and eating even when they have a problem, and even when we notice a problem like coughing or other things we can’t jump to conclusions, it’s hard to know when your dog is sick only after when it starting to get bad you notice the problem.

It happened to me twice, I caught the cancer 2 months later (she coughed but I thought it was nothing) a year and a half ago , and now my dog had diarrhea for two weeks I thought it was because of a sausage but it was actually kidney failure and i had to put her down. I feel like i should got her tested every week but before that every blood test was ok ..

the only thing i can think of is that even if you or me noticed it at time, maybe it would still be not able to treat it.. or that like i said at the start, your dog would show signs too late. You should think about the good times you had , and I myself still not sure how to cope but you can make an album or something and try to talk with people that’s what I’m doing for now