I just got back from the vet and can now genuinely say I know how you feel. Our Shammy is now on the other side too.
Man, I am as sorry for your loss as his, it's a tough nut whenever and to whoever it happens to. The sadness I felt losing my two, back to back in March and April is as fresh on my mind as if it were yesterday.
My new guy gives me comfort, but he is in and of himself, no dog ever replaces another, they are just another furry heart to love...