The holidays aren't joyous for everyone. This time of year can bring stress and feelings of loneliness. Exercise, focusing on positive relationships, and doing things that you find rewarding can help with depression. Get tips on what to do if you feel depressed. Keep in mind that winter depression could be a sign of seasonal affective disorder (SAD), which is caused by the lack of sunlight. Treatment for SAD is much like other forms of depression, but may also involve light therapy.