Practice and self-awareness of what you're doing when you relive these moments. Recognize when you're having these destructive thoughts. Tell yourself that such trains of thought are not in any way productive. Find a way to curb these trains of thought. You'll have to develop your own responses, which work for you. e.g. Tell yourself "stop" each and every time you find yourself thinking this way. OR. Consider if you'd every give anyone else such harsh criticism as you are directing inward. You'll find that with practice, and over time, you can unlearn the self-harm that you are inflicting with these thoughts. Get in the habit of being kind to yourself. This will not happen overnight. But you can learn to stop hurting yourself.