Life is not without its challenges, but there is no sense in making it more difficult in your imagination.
Anticipating the worst does not prevent it from coming to pass.
What it does do, however, is ruin your experience of the present.
You simply cannot enjoy your life now if you spend all of your time anticipating a future of conflict, tragedy, and calamity, a future that may never arrive.
Life will not always go smoothly and terrible things will happen along the way, but nothing is made better through worrying.
Focus on what is in front of you, on what you have the power to affect or to change, and let the future worry about itself.