It does take time and work, sweetie, to turn off that loop in your brain. I've been there, too, and I promise it will get better. You can and will soon have only the best BEST BEST memories of Otis in you; only the best. He knew you did all you could, and you did do all you could, and that will sink in with time. In the meantime, feel held and supported and understood in the loving hands of us, your friends, with the beautiful smiling face of Otis looking down and loving you.
Jennifer