Luckily, a concept did come to mind. I started thinking about it, planning it more precisely. But....maybe, I waited too long to actually start it.
And when I actually did, it was a mess. Words refused to come out in the paper. I was always unsure about almost anything.
Characterization, world, fantasy elements, and of course, the actual concept. There was so much work undone.
That wasn't nearly what actually bothered me. My problem was, in my leisure time, my mind would refuse to dig into those things. It was actually more interested in other things. Other characters in other situations always kept it filled.
And then I learned that the actual place to find a story to write isn't the bookshelf. It is the dreams, daydreams, where there are the stories ready to be told.
Now, after pausing my fantasy project and starting off the other one. I have completed my concept building completely, working on detailed outlining (kind of writing the first draft) and researching. I am so excited, all my work is going on so passionately. Almost everything is being work out on its own.
So, I would say that from now on, pick your projects from where you dream. Not your bookshelf, it will work miracles on your productivity.