My prayers are with everyone who has been effected by the Boston Marathon tragedy tonight. However, as important as it is to be aware of the news, especially if you or someone you know has been effected, listening to the news report ceaselessly on something disturbing can well, disturb you.
I've been told by psych counselors before that people with depression shouldn't even watch the news. The media tends to sensationalize traumas and that can lead to more depression, anxiety and even paranoia. If you have already been disturbed by watching today's news, please turn it off (if you haven't already) and get help. Get in contact with a family member or friend, call a crisis hotline or get outside in nature.
Whatever you do, remember that the media can trigger strong emotions and you need to know when to turn it off.