Someone once said that worrying is praying for things you don't want to happen.  What a great saying, and, like all sayings, there's a lot of truth in it.  When you think about it, praying is when you concentrate on one thing and then you meditate or "pray" on it to the exclusion of all else.  Usually, too, when you pray you put a lot of emotion into it and, of course, you have a lot of faith in what you are praying about.  When you think about it, isn't that what you do when you worry about something as well?