Overthinking has been a big problem in most of the peoples life. Gives you a negative attitude, affects your relations with friends, family etc. How can you possibly stop yourself from overthinking when probably you have no control of what to think?
Reflect on Thoughts
Burying the problem for too long can make you an unproductive person, but this problem can be helped by doing a brief reflection.
Spend 20 minutes to "me time" in your daily schedule. During that period, let yourself dissolve into reflection or think about whatever you want.
When it's over, move somewhere else and do what makes your heart happy.