Depression

Depression is a mood disorder which causes feelings of extreme sadness and loss of interest, persistently. Major depressive disorder or clinical depression affects how you feel, think, behave, and leads to a variety of physical and emotional issues. You may have challenges doing normal daily activities and may feel as if life is not worth living.
More than just feeling blue, depression is not a weakness, and merely snapping out of it is next to impossible. Long-term treatment may be required to deal with major depression. Do not get discouraged; most people with depression feel better with psychotherapy, medication, or both. At times depression can evolve from unresolved grief from loss of a loved one.