At times there is so much suffering in the world that a sensitive person finds it difficult to tolerate. The Brisker Rav, Rabbi Yitzhak Zev Soloveitchik, applied the following Talmudic statement as his advice for such people in such times: "He who wants to live should act as if he were dead."
There are times when human suffering is so great that a person who feels the suffering of others will simply not be able to continue living. While we have an obligation to feel the suffering of others, we should protect ourselves from overdoing it and destroying ourselves.
At times, said the Brisker Rav, we should adopt an attitude as if we were no longer alive and only then will we be able to exist.
(Moadim U'zmanim; Rabbi Pliskin's Gateway to Happiness, p.257)