A major procrastinator? We could have a procrastination contest! I bet I'd win. Problem is getting around to creating the contest. Maybe next year.

On a more serious note, you talked about expanding a short story idea into a novel. Long ago, I wrote a 1000 word short story for "Invalid Item"  . Later it grew to 3000 words. And then some of the core ideas of the world I'd created became my first NaNo. I'm pointing this out because I'd urge you to not feel constrained by your original story idea. Maybe think about how other ideas, other characters, other plotlines can merge with it - expand the universe, if not the story itself.

Just a suggestion, but it beats giving up - or waiting until next year.