Worry is good for only one thing, and that is to pull you out of the present. If you worry about something that has already happened, you will be pulled into the past. And if you worry about something that may happen, you will be pulled into the future. And since you can live only in the present, this is self-defeating. If you can do something about what you are worrying about, then do it and stop worrying. If you can’t do something about it, then realize that you can’t affect it, and stop worrying.