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?
There are many reasons why a person becomes overthinking, one of which is trauma, maybe he or she has experienced something bad or seen a bad condition, which causes uncontrollable overthinking. Overthinking is part of insecurity and depression, so it is important to manage your own thoughts, continue read good books and always discuss problems with those closest to you to get natural healing
or this can also be a sign of less security , some people experienced being taking advantaged
before and that leads them to overthink in many thing specially those in which near to come and
they are not comfortable .
One thing that's helped me is trying to focus on the present moment instead of getting lost in what-ifs. Mindfulness techniques, like deep breathing or meditation, can be super useful for this.
that is really a much effective way mate , to focus in the present and let the future comes
but make sure that you are also ready facing whats coming.