There's nothing like the sudden crash of discouragement that follows a period of solid, positive action. You've been doing all the right things, making great progress, and then suddenly find yourself in a blue funk, utterly depressed by the seeming futility of your actions. It's an emotional sinkhole.
I find that increasing my understanding often gives me a feeling of control over situations that otherwise leave me feeling helpless. I'm going to start by defining the word, "discouragement":
: the act of making something less likely to happen or of making people less likely to do something
: a feeling of having lost hope or confidence