The CBT cycle tells us that our thoughts, feelings, and behaviors all impact each other.
Say I have the thought “I am going to fail my presentation.” That thought would likely make me feel badly. Because I’m feeling scared and nervous, I might then behave poorly–giving a bad presentation. Then, I’ll have the thought “I can’t do anything right.” And the cycle will continue.
CBT teaches skills for interrupting negative cycles and creating more positive cycles.