I'd love to read the work-in-progress.

the voice of my limited experience: if you're early enough in the depression onset that you can, please do everything you can manage to head it off, like get outside (sunlight), move more (exercise), help other people (being needed), even counseling or medication if that works for you. good luck! the brain weasels are not to be taken lightly, and I think you're dead-on right about the depression coming on causing your other troubles, rather than the other way around.