Sorry for your loss and I know the decision was difficult. I have been through that twice and it never is easy. As responsible pet owners we have to think of the animal rather than our own feelings. An aged or sick dog who is in pain is not living a quality life. Animals, unlike humans don't have the intellect to fear death (getting old) but do suffer with pain. IMO it is wrong to subject a loved pet to pain and suffering just to have them stay with you a little longer. I hope your tomorrow is better than today.