Yes, I've been there when working on art quilts that I have designed myself. It's usually a result of having too many ideas in my head about what direction I want to go in with a particular project.
I find that setting some kind of limits helps. So for example, I might decide to limit the number of different fabrics I'm going to start with. Then I will put away everything else so I'm not distracted by possibilities, until I get going with the limited selection and then if I want to add other things in I will shop my stash. Don't know if there is some way you could do something similar with your project.
Rob