Write down your feelings. Set small goals. Sometimes when our thinking becomes constricted we set goals which are almost unachieveable and then feel worse when we cannot reach them. Recognize that this is a rough time right now and that you will need to be kind to yourself. Exercise can help when we are feeling down.
Depression often involves biological as well as social factors.
Exercise does help to address some of the biological factors. Postpone any decision to end your life. There is no reason that you have to make that decision now. Many people report that by postponing a decision to die they found that life did change, they got the help they needed and live fulfilling lives. When we are feeling down and unhappy, it's easy to forget how important we are to other people.