Feeling down every once in a while, is a standard part of life, however when feelings such as hopelessness and despair takes over your mind and won't disappear completely, you might have depression. A lot more than just sadness in response to life's challenges and setbacks, major depression changes how you think, feel, and function in day to day activities. It can hinder your capability to work, research, eat, sleep, and revel in life. Just looking to get during the day can be mind-boggling.