Bill, I am so sorry for the loss of your friend. I hope you will soon be able to find comfort in knowing that you not only gave him a great life, but you gave him a compassionate crossing. Being able to let him go with dignity, and with you there, is something a lot of pets, and even some people don't get. He did trust you, and you gave him that beautiful gift. I could only hope that when my times comes, I have eyes as loving as yours to look into as I pass.
I can see through your posts, and from experience, that the feelings of guilt are hard to avoid, even though we took great care of our furry friends. This too is normal, but damn if it doesn't hurt like hell. Losing a pet is as traumatic as losing a human close to us. Don't berate yourself for crying, and don't hesitate to reach out for support. Pet lovers understand and there is help available through the ASPCA if you would like [DLMURL]http://www.aspca.org/pet-care/pet-loss/[/DLMURL] There are also several books available that can help tremendously right now. One that helped me was, "How to Roar: Pet Loss Grief Recovery".
I know those are all just words, but do know that we all understand and share your grief.