Hey there Allan,
I was reluctant to post because my own pain still lingers. I too had to put my pet/pal/ to sleep. It was three months ago but I guess not enough water has yet flowed under that bridge .
I know what you're going through. The pain won't go away soon and in fact shouldn't. It shows how much you loved your pal. But eventually it will lessen and be repalced by fond memories of the good times you were able to share over the years.
My pet/pal was "merely" a cat, Harley and I must have really loved him............