I am very sorry to hear of your loss. In my experience what makes losing a dog so difficult is their total innocence (I have had 5, not including the one pictured in my posts). In the end they look to me as their leader (the leader thing maybe just in my imagination

) for help and there is none to give. All we have to give is love and comfort. From your posts it sounds like Kirby had a special life and you will take comfort in that.
When I lost my previous dog, it was very difficult, we were as close as any dog I have ever had. After she passed, I decided to not get another one, it did not seem worth it.
That lasted for 3 years, when I decided it was time again. I find it hard now to believe I waited three years. To me the pain, albeit massive is a price I am willing to pay for all of the good times.
As I write this my heart tugs at the memory of Casey, the new dog is looking at me like I have two heads, waiting to go somewhere, waiting for me to get moving. I will face the pain of losing her in the future (she is 7), but I am so happy she is here right now.