April - the season I usually feel fresh, but I am now depressed, why?

In the morning,I walked from home as far as Kawazoe routinely. While walking,I was feeling blue.It is spring, April, the season when I always feel fresh and hopeful every year. But, why am I feeling so blue? When I think of the people in the disaster areas stricken by the earthquake and tsunami, I shouldn't be feeling like that. They are in far more painful and difficult situation. I will try something new. I must restart.
After returning home, I phoned the international division of the municipal office,saying I would like to quit my voluntary work of teaching Japanese. The reason was there were only two students,but both of them were often absent.
A few days ago, I submitted an application form to attend a class for learning how to communicate in English. Though I am qualified to work as a tourist guide in English,I wanted to learn English from the beginning. If I meet fresh, young people, I think I will be motivated to do something new. Be humble,and don't bother other people,most of whom,maybe,are beginners.