Take comfort in knowing that you were able to do what had to be done for your true friend. I went through that about 5 years ago, and couldn't find the strength. I had a Black Lab that I'd been through so much with, and he died a few months before turning 18 years old. When he was 4 weeks old, we picked each other. At 6 months old, I ran over him with my pickup up at my duckclub the evening before duck season opened. I cried for hours and hours, but in the end he was fine. He had a broken pelvis and split femur, but it all healed well. When he was about 5, he jumped over the bow of my boat when we were chasing after a crippled duck, and I ran over him. I thought he was gonna come up with half his head missing form the propeller, but he was ok, just coughing and choking from swallowing some water. When he was about 9 he broke through the ice while we were out duck hunting and all I could see was his front paws and nose sticking out. I jumped into my boat and crashed through the ice, got close and wrapped the bow rope around my wrist and slid out onto the ice and pulled him free. He damned near drowned and had hypothermia pretty bad after that one. Had to take him back to the clubhouse and put him next to a heater for hours and give him warm broth to get him to stop shivering.
His last few years, we had to lift him off the boat dock into the boat, and then from the boat into our duck blind. My younger lab, who's laying next to me as I write this, would retrieve the birds, and then let him take them from her, and he'd give them to me before going to lay back down and go to sleep until I began calling the next flock.
He was damned near blind, could barely walk or hear, but he'd been my hunting partner for over 17 years. I couldn't do what you found the strength to do. I was finally gonna put him down when my wife and daughter were away, and the night before we were gonna take him to the vet, he died in our backyard. He bailed me out one last time. I took him up to my duckclub the next day, laid him in my boat and drove him all around the marsh, visiting all of our old duck blinds one last time. I then went out and dug a grave on a mound and buried him with his vest and my favorite jacket to the west of our favorite blind. I get to think about him nearly every time I'm out there.
Slide, you did the right thing for your partner. Now, its time to go get another dog soon and start building that special relationship with a new buddy. I'll be at that point again in a few years, and it hurts like hell when you have to go through it, but that's because they are so special to us. You'll never forget him, but a new buddy will make it a sweet memory of what you had, and what you'll get to look forward to.
Pretty selfish on my part but just not ready I guess.
