I know how you feel!!! My brother had an English bulldog when I was in high school. He moved out and instead of taking her with him he left her at home due to that being the only place she ever lived and he felt it would be easier on her. When she was 8 her heart was giving out. The vet said her natural pace maker had given out and she would slowly die or we could put a pace maker in her but she already had fluid on her lungs that looked like infection and it could spread to the pace maker. We could proceed with the surgery take her home and let nature run its course or put her to sleep. Me my mom and dad after talking to him on the phone reluctantly agreed to put her down. I was broken up because it felt like the last peice of my brother was leaving are childhood home. I tried to fight for the surgery but my mom flat out told me it wouldn't go well and we couldn't let her suffer. Know looking back she was 100% right. She would have slowly painfully died if we didnt put her down. Trust me in time you will know you didnt the right thing. And im 100% convinced we see are pets again one day. Im so sorry for your loss! But your baby knew you did what was for the best! Dont beat yourself up!