If you live in a warm climate, get out and exercise, jog, walk, bike rides. Cold climate, maybe a gym unless you have some exercise equipment at home.
Yoga or meditation (it can clear away the junk stuff so you can work on the real things and issues in life that matter).
Interests and hobbies, join a group.
You may have a point about getting a SAD light.
Depression is a part of mental health to be taken seriously. If you are in a large community/town/city there may be a facility for this or seek out a psychologist.
Take care & be good to yourself. Think positive thoughts.
Just a few thoughts.
Jamie