So sorry to hear of your loss, Scuba.
We lost out own pup on 4/10, at 10:20pm. He was only nine and a half years old, and he was in good health, until he wasn’t. He had a normal day, ate normally, tools his normal morning and evening walks, we played tug pf war after dinner, just like every day. Then, we took him to potty at about quarter after 10, and he didn’t immediately return. We found him belly down, staring at the pool. My wife called to him and he finally got up and came in, but belly flopped again on his way to his bed, and had labored breathing. After maybe 10 breaths, and us frantically trying to revive him, he flopped on his side and expired. We raced him to the emergency vet, to no avail. He was already gone.
We are heartbroken. I’ve largely tried to replace the bad memory of his loss with all of the good memories that he brought us. My wife, however, is still just devastated. He was her little boy (and our girl dog is my little girl, but he was my tug of war buddy). But whenever we think about “why” it just becomes too painful again. We don’t know the “why” and decided against necropsy since it wouldn’t bring him back. He’s just gone too soon. They bring so much love when they join your family but the pain of losing them is indescribable, especially when you don’t even get to say “goodbye”.