I feel that a fathomless intelligence is within us. The more noise there is in my mind, the less intelligent I feel. The more peaceful my mind, the more I can access this intelligence. A mind that is consistently filled with many thoughts is a mind that is not peaceful, a kind of anxiety is there.

Meditation will teach you how to quiet your mind in a natural way. Start with this excellent article that explains how and why to practice meditation and how it helps create silence in your mind.

What is meditation? How to practice meditation.

Practice meditation regularly for a while, and you will understand how to end overthinking.