I would guess it's because you have never really learned what your talents, skills, and interests are. Ultimately we need to pick a major and stick with it. I was interested in a lot of subjects after I took a course or two in them, but I stuck with what I originally started with--and double majored. That is a possibility. Or a major and a minor.....

It could be that now you are getting more and more afraid of making mistakes, so you are avoiding making the decision.

I suggest you go to your school's counseling office and see what inventories they have available for you to take that will show you your best skills, etc. At least you would something "concrete" to help you choose.