Scripture teaches us that we need to fight against negative self talk:
The weapons we use are not human ones. Our weapons have power from God and can destroy the enemy’s strong places. We destroy people’s arguments, and we tear down every proud idea that raises itself against the knowledge of God. We also capture every thought and make it give up and obey Christ.
You've seen examples of negative and positive thinking. You've learned how to turn it around. Positive affirmations will transform your life. Let your faith in God guide you through the process.