re: How did y'all deal with putting a dog down

I was 16 when I had to put down my 6 year old dachshund for the same issue you mentioned. That was in 2013. I have never cried more in my life and it was the hardest decision I had to face. That said, I knew quality of life would not be ideal for her and her dragging her legs was the most heartbreaking thing.
Here is a pic of Sundae.