Just know that Semmi is probably not upset about this, just maybe a little confused over the changes. It is us humans that feel the horrible wrenching when we realize what is coming. My test for my angel Sam was whether he wagged when someone petted him, whether he was in pain, and whether he was able to eat. The day he didn't wag when I petted him I knew it was time. However, I think I actually waited too long, partly because everything with Sam happend around the time of my Grandmother's death and funeral. He was steadily losing weight, could barely get around to his water and food, and only got up from his bed to eat and pee. I probably waited about 2 weeks too late.
I have to tell you that I still feel my heart break every time I think about it. I try not to think about it, actually, even though it was absolutely the best thing for Sam. I felt guilty for so long afterward, but I finally stopped that about three months ago. I don't think I'll ever actually "get over" it, but that's just part of what we have to face since we live much longer than our furry friends.
I'll be thinking of you. Just know that whatever you decide will be the best for Semmi, no matter what!!!!!!