I never have enough time to do what I planed to do.
perhaps depression is caused by lack of interests? I study consciousness and find that mental energy comes from variety of interests and enterprises. Love, family and main occupation are the necessary sources of mental energy, however everyone needs secondary back up of hobbys, entertainment, sport, music and general variety of nature, landscape and leisure time.
The weather and seasons also affect mental energy. Lenght of daylight, dull,cloudy days, prolonged rain and long summer heat are causes of down time.
The problem is that depression creeps up on a person unannounced and often even the depressed person does not know what is wrong.
I always try to keep some activite in reserve incase boredom creeps up, so I don'nt have time to brood.