As for knowing what you are doing with yourself . . . not much I have to offer you there. However, I think the best attitude (usually I would just say this is just my attitude, but increasingly I think it is a pretty generalizable principle) is to just study what you want and figure out the career/post-collegiate-stuff later. I would say just follow your passion and either 1) see if you can try to mold it into more or less one predefined discipline (regardless of whether it is ‘practical’ or ‘marketable’) or 2) see if you can take all the disparate pieces and try to scrape together some sort of interdisciplinary or individually designed major.

Realistically, unless you do something like engineering, hard science, or computer science your major is probably not really going to directly lead into any one career. I think increasingly people get a degree and then find a career and get trained in that career after college – obviously using the college experience as a resource (knowing how to write, communicate, think analytically, problem solve, etc.) but probably not directly applicably so. Secondary education in the United States, especially at the high-prestige level of Stanford, is a lot more about well-rounded education and less about job training than most of the rest of the world. The job market knows this.

Anyway, it is true that it is a Friday, and there is the weekend to look forward to to chew over things.