Harry was just thinking that all he needed was for Dumbledore's pet bird to die while he was all alone in the office with it, when the bird burst into flames.
J. K. RowlingDepression is the most unpleasant thing I have ever experienced. . . . It is that absence of being able to envisage that you will ever be cheerful again. The absence of hope. That very deadened feeling, which is so very different from feeling sad. Sad hurts but it's a healthy feeling. It is a necessary thing to feel. Depression is very different.
J. K. Rowling