Usually if you are not sure about an idea it means it didnt grow on you. Many people have issues with multiple ideas popping in their heads. I would suggest planning each idea (making mini business/action plan). After 10-20 scraped plans like that (that you spend at least ~10 hours developing) you will be more willing to commit to one bigger idea and stop wasting your time. This worked for me and first time in my life I committed to project that is 1 year long. Good luck!