Did you come up with the melody first and then harmonize the bass afterwards?
It was all done simultaneously. To be quite honest, I don't know where it comes from, but when I start writing stuff evolves. I try to let the music itself tell me where to go. Then, after I get it all sketched out, I go in and fix up this and that and start looking at the overall structure.
All of my compising starts off with me just improvising sone stuff on the piano, and then I start writing my thoughts down, and then I massage them into a whole. It's kind of hard to explain, I guess it's why it's art and not science (for me anyway