You control your attention to your thoughts. You and you alone. So filter and embrace the positive ones when they pass through. Let go of the negative ones that have not happened. Do this every day so it becomes your thought pattern. Trust it and practice it until it become second nature. Over and over again. Soon you will be redirecting your mind. The negative ones will become a slight mummer off in the distance, and the positive ones will become a beautiful choir front and center.