I've just started another story and I'm having the same problem. At this early stage I'm not sure the whole idea isn't going to come across terribly corny and contrived. Unfortunately, being a discovery writer, I won't find out until I write it. Another problem was I couldn't start until I had the main character's name. Placeholder names don't work for me, I can't change the name later as the character grows into it. One day it might be fun to start with a silly character name and see where it takes me. For now I've got this story to keep me going.
I'm trying to decide about doing NaNoWriMo this year. I'd like to, in that it's done wonders for my productivity in the past, although I'm not sure I have the mental energy to sustain it this year. Probably it's the idea of doing it I'm finding attractive, since I remember how much I enjoyed previous years. Perhaps I'll sign up to a shorter project instead, a half NaNo or a story a week. I certainly need to get some momentum back up again.