You do not need fight Worry - that is not the way to overcome the habit. Just practice concentration, and then learn to concentrate upon something right before you, and you will find that the worry thought has vanished.
The mind can think of but one thing at a time, and if you concentrate upon a bright thing, the other thing will fade away. There are better ways of overcoming objectionable thoughts than by fighting them. Learn to concentrate upon thoughts of an opposite character, and the problem is solved.
When the mind is full of worry thoughts, it cannot find time to work out plans to benefit you. But when you have concentrated on bright, helpful thoughts, you will discover that it will start to work subconsciously; and when the time comes you will find all sorts of plans and methods by which you will be able to meet the demands on you.
Keep your mental attitude right, and all things will be added unto you. There is no sense in worrying; nothing has ever been gained by it, and nothing ever will be. Bright, cheerful and happy thoughts attract bright, cheerful and happy things to us - worry drives them away. Cultivate the right mental attitude.