I was touched by your story. I believe dogs do reincarnate, as do we, and we meet them again or they wait and join us in the "between lives" time. I've had seven dogs as an adult, and the first one was Tommy, who was the canine equivalent of a soul mate. When Tommy passed away I asked him to come back and find me if he could. That was 13 years ago and he did not, but now he is probably in his next life or approaching it so one can always hope he comes back. As for the decision to let your ill dog go, it was the kindest and most compassionate thing you could have done for your old dog. I've sat with three of my four dogs as they passed over, and the fourth had a brain tumor and didn't recognize me so I was not there when she passed as she was not herself. I don't think the young dogs you met later, if one of them was your friend, were blaming you as much as saying "hello!" Dogs, living or gone, do not blame. They are briefly saddened if we get angry at them or leave them, but always forgive immediately.