Those of us that are older can relate even more with the guilt and pain you feel, but you shouldn't feel the guilt, this was out of your hands, the pain you must feel, it will lesson with time but will always remain, I know, I have out lived several of my beloved heart horses. The first one was my first, she had epm and couldn't stand even with a sling, back in the day before there was any treatment available, broke my heart when the vet put the first needle in her neck. She looked at me with those liquid dark eyes, filled with so much love in them. My second was her son, my show and trail buddy, woke up one morning he was in shock, twisted gut, too late to save him at least I hhad him for 30 years. Makes me cry just typing this. My youngest daughter had to decide to put down her beloved show/trail mare at age 30, she had cushings and bad/severe founder. The one thing I do know is we are all blessed to have them for just a little while, and we are their angels, as we love them so much we don't allow them to suffer, not for a minute, we are there to protect them from suffering. So Ashley stop second quessing yourself, you did the right thing.