You've lost interest in food, sex, and the things that used to make life worth living. Concentrating on your studies is difficult and you've become nonproductive in getting your work done. You have little energy for activities and feel constantly fatigued. You're sad, unhappy, anxious. These symptoms last for weeks, months.
More time goes by, nothing improves.
Time slows down and minutes seem like hours. An alarming one in five women and one in ten men will feel this way over the course of their lifetimes. They aren't lazy and they aren't making it up. They have depression. Personality factors such as undue dependency and low self-esteem may also be associated with a vulnerability to depression.