Don't just do something. Just sit there!
When depression and despair strikes, what choice do we spiritual travelers have but to sit there in silence and face it? Sure, there are many who try to plaster it over with Prozac, alcohol or fake entertainment, but it is a wasted opportunity for spiritual progress. Instead, we should use the blues to experience the workings of our ego, and literally see in front of our astonished eyes how parts of our "I" peels off and something new emerges.
The opposite energy is when the ego wants something; when we aspire and fantasize. It may be a much nicer feeling to have than being in depression, but it can be the same deviation from the SELF that will only come back to haunt us. Depression is yin energy, as we are helplessly exposed to the ego's wrath; desiring and fantasizing is yang energy. We want to take the initiative to make us better off. In either situation, to experience your SELF, just sit there and observe what's going on without doing anything.
When you are in depression, can you observe how you even beat yourself up over the fact that you are so weak and so helpless? Similarly, you might even judge yourself for having longings and aspiration. See the futility in that mental (not so) merry-go-around. Just sit there and observe. Don't just do something, awaken to your SELF.