Being worried is a misguided attempt to control life--life that hasn't taken place yet. As Mark Twain once put it, "I've worried about a lot of things in my life, most of which have never happened." Worry doesn't add up. Trying to control life by anticipatory worrying only subtracts from it.
Think of worry as a form of psychological friction, an anticipation of future chaos and things going wrong (we don't worry about things going right). Whether you try to control your life by worrying, over-thinking, ruminating, being too cautious, fearful or doubtful; control and worry are never the answer and, if you’re stumbling emotionally in life, they're always at the root of the problem.
Rather than worrying about an uncertain or chaotic future, stay focused on the here-and-now facts of your life. If, for example, you have high cholesterol (which would be a fact), rather than worrying about having a heart attack, address the facts by eating more healthfully, getting more exercise, medication, and so on.
Dealing with facts keeps you effectively in the present with a bonus of eliminating the anxiety associated with anticipating doom and gloom.