We all have stories, decisions, moments that haunt us. Take comfort in this fact, no one is immune. Living a regret-free life is impossible, and even psychotic, so allow the feeling, learn from it and then forgive yourself. Besides, if you had made a different choice you’d eventually just wind up with a different mistake. They’re inevitable with this whole being human thing, remember? Reliving pain doesn’t “fix” the past, it only debilitates your future.