Over the next week, make a list of things you are worried about. At the end of the week put that list to the side and for the following month keep another list of which, if any, of those worries actually happened. Now compare the two lists.
How much time and energy did you waste on things that never even materialized? Of the things that DID happen, think about whether your ruminations had any impact on the eventual outcome.
If you have fear of some pain or suffering, you should examine whether there is anything you can do about it. If you can, there is no need to worry about it; if you cannot do anything, then there is also no need to worry.
– The Dalai Lama