I honestly don't think you ever get out of this feeling. I'm still in active treatment and so I'm not as experienced as many of the survivors here but I think something has fundamentally "slipped" in my psyche. The best I can hope for, I think, is to absorb this and keep on going. It doesn't mean that I can't rage at the injustice of fortune. So, @12paws - I don't think you're wrong in what you're feeling (I was going to use another phrase but I CAN'T REMEMBER HOW TO SPELL ANYMORE).
And I can easily imagine how losing your dog has stirred things up. We love our pets and they return that love and give us support. I lost my beautiful cat in traumatic circumstances a few years ago, and while we now have another wonderful moggie, I will never forget Merls (or for that matter, my cats that came before). I have tears in my eyes, typing this.