Ah, I see. I've been there, too, plenty of times. :/ Hopefully the muse is kinder in the upcoming weeks. It always comes back, sooner or later, I think
For me, my plot had gotten entangled and fuzzy and really just a disorganized mess of ideas. I'm currently trying to iron it out, in between working on original fiction.
Out of curiosity, do you have any other creative pursuits you engage in, in addition to fanfic writing?