Sometimes the hardest decisions need to be made out of love. I too was faced with the same situation 3 years ago with my Lab, Abby. It was the hardest and loneliest thing I ever had to face but I knew that it was the right things to do after speaking to our vet. I loved her so much and knew that she needed to be in peace.
You are in my thoughts and prayers for your precious baby. Welcome to YT~during this very emotional time.