October Novel Prep Challenge

I almost didn't sign up for the prep challenge because I just wasn't confident I knew what story I wanted to commit to. I felt really good at the beginning of the month. We're about halfway through now, I've done about half the assignments, and I really don't think this is the book I want to write this November.

I'm a big believer in working on the project you have the most inspiration for at that moment, and right now that book just happens to be something else.

Does anyone else go through this? Can anyone give me advice on what to do?