I can't decide what career I'd like to go in. Could anybody give me some advice?

Where do I begin? I'm fifteen-years-old, and going into my Junior year in September. I've always been a sort of Renaissance-kinda guy, as in, I've always had a lot of things that interested me. I've always been a superb reader and writer, and writing short stories have always been a hobby of mine. However, I also co-manage a rather successful (around the area) mobile DJ Entertainment business, and taking it to the next level has always interested me. Along with the DJing business, I've often wondered about going into the music business industry, because I've always loved editing and making my own music (I play a bit of piano). I also have researched tons of information on evolutionary biology, and know more about it than most people should be bothered to know, simply because it fascinates me. Because evolution is such a controversial topic, I became quite a capable debater, so I contemplated pursuing a career as a lawyer, but then I heard that you have to sell your soul or something similar to be a lawyer, plus the overall atmosphere of the field is depressing from what I've heard. I also know how to work animation programs and make cartoons. One final thing I am interested in is the study of the mind, why we do certain things and act in certain ways, based on my knowledge of evolutionary biology. Overall, I do a lot of things. Unfortunately, the result of this has left me utterly confused as to what I want to do when I graduate high school, and now I'm a little frightened that I'll not only make the wrong career choice, but send myself down a wrong overall road. Not only this, but I'm worried that another fault will make it hard for me to decide. You see, although I'm at least somewhat knowledgable in many different things, I am utterly dreadful at math. I failed it this year, currently taking an online summer course in order to p it with a 67%, and the 64% I've recieved in it this year has brought me to the lower third of my cl. Which is beyond depressing for me, because I like to aim high, you know? Even my math teacher has said that only the top half of the cl actually get into college, and that thought, frankly, scares the hell out of me. In other words, I'm determined to make something out of myself, but I can't decide what the blue f$#@ I want to do, and I'm afraid that my math grades will keep me down and out of colleges overall (my family isn't the richest on the block, either). Plus, I've been seeing senior friends get scholarships, and I'm realizing that *I'm* probably not going to get one, seeing as I can't focus on one thing and I'm...basically all over the place with my chosen elective. Freshman year it was theater and film, sopre year it was Spanish and Visual Art, next year it's gonna be Business Law...I'm all over the place. So, does anybody, anybody at ALL, have any sort of advice to help me get the heck out of this conflict? Much appreciated--this has been driving me crazy for months upon months.