Frank, I am so sorry for your loss. Having to put a dear friend down is the most gut wrenching thing imaginable.
The last time I faced that, I questioned my sanity for being so utterly devastated by the loss of a pet after having lost my grandparents, parents and so many relatives and good friends over the years. But no, I wasn't insane. I was heartbroken by the loss of my faithful companion.
In time, that heartbreak will slowly give way to beautiful memories. I believe a good pet can make us a little better for having known them.
You are in my prayers.