Very often, people get sad when they are tired and overworked. Lack of sleep, constant stress at work – here from anyone not strong enough to fight life's small troubles. In a state of heightened fatigue natural optimism of the man is fading away, he is sad. So for that your natural cheerfulness woke up to any situation not seen in the black light and not tired, need to rest and sleep. If now it can be done, then at least just relax and think about something pleasant.
Typically, when a person's life balanced and harmonious, the reasons for the sadness practically does not occur. When accumulated a lot of unfinished tasks, you feel that you are above it hang the obligations, liabilities and the need to do something, the hands themselves are omitted, it is sad. It is better not to bring the situation to such an extent, and try to keep life going steadily and quietly, but things were always fine.
Sadness is chronic. Whatever you do man, nothing pleases him, he is sad all the time. In this case you should try to change the situation, to recover the vacation, any trip to visit friends in another city or another country, at least for a few days. At this time, try to abstract from the current situation to the maximum, to get out of it. Better turn your cell phone off, not check my email. A change of scenery awakens the latent powers of man, reveals the resources that sadness as a hand shoots, but the cases themselves will be resolved when you return.
Usually, sadness comes suddenly, but not for long, but if it became a phenomenon frequent and prolonged, then it is discouragement, apathy or even depression. In the case when to deal with it yourself does not work, consult a psychologist or psychiatrist. The cause of depression can be psychological, but it so happens that it is caused by certain diseases. For example, for a strongly reduced level of hemoglobin people fall into depression, which can be quite mess with.
Short-term sadness is best to try to dispel with the same short-term pleasure. Go for a walk, dance, call a good friend, buy yourself something long planned, but I kept putting it off, watch a good movie, start to plan a vacation, sing and dance at your pleasure, anything that brings you satisfaction and joy.