i have a similar problem, in the opposite direction. i package up my project fabric along with the pattern. when i go looking for the pattern i can't remember where it is. especially frustrating when it is a book. right now i am looking for a book i purchased for a log cabin tree skirt.
like someone else said it will come to you after you have made alternate plans. it just means that the new project was more important than the old. right? that's my story and i am sticking to it.