I'm still not sure what I want to do for a career. What is the best way to find out why I would really like to do?

First note (deliberately not answering your question!), if the common denominator for all your things is science (even if that includes engineering or programming), keep taking as much math as you can, and consider taking a statistics course if available (not all high schools will have one).

Now that that's out of the way, there's gonna be a limited amount of exposure you can get in high school, so focus on breadth. Get one or two courses in as many different things as you can get your hands on. If you have extra time, check out open course stuff on MIT, Coursera, etc., and see if anything looks interesting there.

Also note that what you think is what you'll do at the end of your senior year and what you end up doing after you graduate Uni may be very different (certainly was for me).

Final note (same as first note) - my suggestion to take as much breadth as possible should not come at the expense of taking as much math as you can.

If there's a choice between broadening out in HS and taking another science course and taking a math course instead, choose the math course (assuming it will be new & challenging). The "science" you tend to learn in High School will not matter 4 years later, because it will be so completely different from what you're doing, that one day you'll wake up in chem lab after pipetting your thousandth test tube and think back at your sophomore chemistry class and laugh at how it had nothing to do with actual chemistry.

The math you learn in high school will force your brain to learn to think logically and mathematically, which will make your life in Uni (and maybe after Uni, but mostly in Uni) way much nicer, and give you more mental time to learn the rest of the stuff.