You didn't do anything wrong. As someone who has also experienced violence and tragedy (as many, many people have), it does feel like the world should stop, that no one should tell jokes or laugh or have a good time ever again because such a massive, incomprehensible thing has happened.

But that's just a feeling. In reality the world keeps going, mail still gets delivered, people still go to work, you still have to comb your hair and do the laundry.