writing and outlines

Out of my many fanfic ideas, today I wrote one down, 1900 words in 80 minutes, for a 2 chapter manga where I may have already written more words than exist in the source. Having cycled it through my imagination for the past few days, and being mostly dialogue, it flowed out pretty well -- and yet I find that even a tiny outline, say of the intended 'beats', might have helped, since I ended up combining two topics back to back when I'd meant for them to be separated by another episode. So that's interesting.