I will try to answer the two aspects of your question.
Particular situation in your plot is probably to benefit from doing some research on what depression is, and how people get out of it. Maybe you can find online or better find a person in your surrounding who had similar or even same issue.
Generally, people get out of depression by accepting their current state and not struggling by wishing it was different or having sorrow for what they have lost. That is a deep transformation which needs to happen within a person to start looking on things from different perspective.
On the writer's block: I guess research, putting things off a bit to cool off, trusting your character and letting it tell you instead of you finding a solution for it, letting things be the way they want instead of finding the "right" thing. Once you free your mind from the concept of doing it "right", you can do it however it works for you as long as it is real in the context provided, and you are the owner of the whole context and the plot within.