Bad news have a way of getting you down. Tragedy, even if it's other people's tragedy, leaves a strong emotional imprint. That's one of the reasons why its important to filter what information you feed your brain. Are you reading papers and watching programs that leave you shocked, disgusted and dismayed?
If you're trying to improve your health you must actively choose your input. When searching for new information and selecting entertainment and input in the form of books, magazines, movies, music, games or TV programs you can ask yourself: "Is this bringing joy, hope and inspiration into my life?" ... and if not, why spend time on it?