I'm starting to fall into a depression again. What can I do? I had my mood under control for over ten years.
Unfortunately for many people depression is a recurring illness; many who have one episode go on to have a second and third episode if untreated.
If you are noticing signs of a recurrence the best thing to do is seek professional help as soon as possible. If you were or are in the treatment of a mental health professional, then make an appointment to see that person again. If not, then find someone new. There are many proven effective treatments, including several classes of medication as well as several forms of therapy.