Beliefs and blueprints
We experience something, we think about what we experienced, and our thinking makes us feel something. That feeling is sometimes stress and anxiety towards what happened or is happening. But, what we think is based on a belief about what happened or is happening. The feelings of stress and anxiety are a result of that experience not measuring up to a blueprint of how we feel it ought to have been. Adjust the belief, reevaluate the blueprint, and you find the stress melts away.