Mind is the only organ that is constantly awake and busy.  By altering our states of mind we can also alter our states of being. 
Well this week we are looking at how we can  stop an overreactive mind. 
Metacognition 
We are  three dimensional  beings having metacognitiveabilities. We have the power to observe our own thoughts and self. We can decide  how we want to feel, think and act. Having this ability enables us to self reflect and scrutinize ourselves and make a plan to modify our behaviours so we can produce more  desirable outcomes.
To do this start observing all aspects of your present personality. Since they primarly operate at the level of conscious awarenss, you will have to go within and look at these elements yu probably havent been aware of before.

Challenge your thoughts
Challenge your thoughts by asking the following questions:
Why do I think this will happen?Is there any evidence to support this thought?What are other possible Interpretations?Will this matter in 1-5 years from now?Do I have a solution that I can put to action?
Consider the wider Perspective
When overthinking you narrow your perspective down to few details  and lose touch with big picture. To regain perspective , allow yourself to step away from the problem and focus on something else for a period of time.
Take Action
When all you do is spend time inside of your head you discount the most important element i.e. to take action.  Thinking without doing only gets you stuck in your own mental feedback loops. Decisive action  and real-world feedback can often be the best cure for an overactive mind.

Ask for help
Asking for help allows you to surround yourself with people who can provide support and further facilitate in your personal development.