I have no idea what I'm doing

I stayed up past 3am this morning, plotting out something new on stream. Between the five and a half hours last night, and the two hours a few nights before, I think this is the most time I've spent plotting a fic in a long time. After converting everything to an outline page in Scrivener, it's come out to 120 cards, exactly. I don't think I've ever done an outline this big. This is an ambitious as all hell project, and suddenly I'm feeling very overwhelmed.

( Spoilers ahead )