Terrible Sadness

There's no way Kim and I could have known what to expect yesterday morning. Following a nice Thanksgiving, Kim and I had car trouble on the way home. As it turned out, essentially, out car died. After significant mechanic's bills on Friday, it still runs, but the car shakes, one of the cylinders isn't working, and the engine light is still on. The mechanic told us we should get rid of the car. Kim and I thought that was a rough blow, but also expected that the worst was over. We couldn't have been more mistaken.
After taking the dog out yesterday morning, Orion seemed to be in fine spirits and his normal self. Suddenly, though, he collapsed onto the floor and couldn't lift his head or otherwise move. Kim and I rushed him to the vet. By the time we arrived, his breathing was very labored. The vet Xrayed Orion, who couldn't stand, and started giving him fluids.
After waiting anxiously for the results, the Xrays showed that his heart was twice the size it was in September. It seemed likely there was either a tear in his heart or a tumor preventing blood flow. We made arrangements to bring in a veterinary cardiologist for Monday, checked on the dog to find he was still very lethargic and now breathing shallowly, and went to get some fresh air.
Kim and I wouldn't be able to visit Orion on Sunday (vet's policy) and his making it until Monday was very dubious. Since the vet was closing soon, Kim and I had to see him one more time before the end of the day. We felt terribly that he was at the vet's all alone and, probably, very near death.
Upon our return, Orion was still in a crate out back and hooked up to an IV. He didn't look good, was cold, and became increasingly pale. I don't know if Orion was excited to see us or in pain, but he began panting. He breathing continued to fluctuate between slow, deep breaths and rapid, shallow breathing. He seemed to be increasingly uncomfortable and there were a few times I thought he was going to suffocate. It became terribly clear through seeing him and talking to our vet that Orion's chance of survival was minimal and his chance of returning to an appropriate quality of life was virtually nonexistent. In short, his suffering had become too great.
For Kim and I, it had become too painful to watch Orion struggle like that. Even at the end, he desperately tried to lift his head so Kim and I could pet him, hold him, and help him breathe more easily. I think even he knew it was all for not. Without getting into any more of the details, Kim and I put him down at 4pm yesterday.
Kim and I have really struggled to deal with our loss, but feel sadness because of our personal suffering; the fact is, Orion was in such a place that being put down was easily the most best option. It was the right thing to do for him. Kim and I, though, are fraught with sorrow and shocked by the rapidity with which the mighty Orion has fallen. He was also so healthy, happy, and cheerful. He loved to listen to Kim sing, "shake" my hand, and snack on cheese or whatever food Kim dropped on the floor. There was never an occasion whereby Orion didn't love Kim and I, wasn't excited to see us, and didn't do anything he could to put a smile on our faces. He was always such a comfort. And much of our pain comes from the fact that we feel as though we failed our dear Orion and wish we could have done more for his special life. He was completely dependent upon us and, in the end, there was nothing we could do to save him.
Oh no....
Although I think it might be easier for us to deal with the loss by trying to replace Orion with a new puppy, Kim and I are completely unprepared to do so. The fact is, Kim and I could never hope to have a more friendly, smarter, quieter pet; Orion is, literally, irreplacable.
I don't know what more to say at this time so I will, simply, leave you with a few pictures of our beloved and eternal Orion.