I concluded I wanted a bachelor's in environmental studies and a master's in urban planning after having an eye-opening experience and realizing I wanted to do something with the built environment. I then went through college catalogues (which might be easier today, with the internet) and made a list of majors that had something to do with the built environment (including civil engineering and architecture). I eliminated civil engineering because it required so much calculus (a class I dropped out of and never want to see again) and I eliminated architecture because it would involve basically starting from scratch when I already had a couple of years of college. I don't recall what the other majors were, but I thoroughly looked at the requirements for each before finally settling on urban planning (then life got in the way and I have been sidetracked for some time and have no even finished my bachelor's).
Perhaps a similar approach would help you pick a major?
Good luck with this.