Taylor, SAD is Seasonal Affective Disorder. SAD is a type of mild seasonal depression that can be caused by lack of sunlight during the winter. You can go online and buy a light for light therapy. Take a walk in the morning to get your melatonin production up. Take walks and exercise. Consume omega 3's. And eat fish several times a week. Download a meditation app for more support to your brain. All of these tips help depression. If you sink from a mild depressive state into a deeper depression, go to a health care professional immediately for evaluation.