andrzejpw, I teach philosophy at a university, and I'm well acquainted with the uncertainty you are are feeling. Hell, I know it firsthand from my own student days. So please allow me to give you my well-honed response to your consternation (which almost ALL students go through, so don't feel alone in this!).
Look, the very purpose of a university is for you to try out different things, discover what interests you, what you are good at, what you are not good at, to learn and grow. Cliches, yes, but all too true.
What the university is NOT:
1) A glorified trade school (despite the fact that many university administrations and the public at large insists on seeing it as such)
2) A mere formality or holding pen, an annoyance one must endure in order to receive sanction (i.e., degree) to get on with The Rest Of Your Life.
You obviously seem interested more in the sciences than in the liberal arts. Colleges of Science are typically more rigid and narrow with their degree plans, pressuring students to specialize early on - invariably too early, in my opinion. And much to the detriment of one's development, they also tend to de-emphasize the traditional liberal arts, requiring only the bare minimum and not encouraging their students to challenge themselves to go further. By "bare minimum" I mean the dreaded scantron-auditorium-taught by a clueless T.A. requirement. Check around, ask fellow students, particularly upper classmen/women - you CAN avoid these dreaded hellholes if you know whom to take instead. (Believe me, there are no scantrons or route learning exercises in my intro classes!)
I would guess that you must be around 17, 18 years old. I've yet to meet anyone who knows what he or she wants to do with his/her life at that age! I certainly didn't! For the record, as an undergrad I began as a music major, switched to psych, was briefly a linguistics major, dabbled in geology, and finally took two B.A. degrees - one in film and the other in philosophy. (Then combined the two interests in grad school.) I should also add that all of this was occasionally interrupted by stretches away from university life - touring in bands, traveling in Europe, working less than desirable jobs (everything from pizza delivery to substitute teaching to working on a film crew making terrible schlock in Italy). And this is precisely as it should be! My previous majors and sundry adventures were NOT time wasted. Quite the opposite. I learned new things that have stayed with me, led me to different places, taught me so much about myself - what i was good at, what I wasn't so good at after all, what really appealed to me that I never guessed would've appealed to me, etc.
Honestly, relax. Keep yourself open to new ideas and new challenges. You never know what surprises are in store for you or where you'll end up. And this is as true for your personal life as it is for your academic life. DON'T stay home all night studying (well, sometimes ...), DO meet new friends, DO have as much sex and wild adventures as is possible, DON'T hesitate to change your mind and adjust your plans (and major) accordingly. I've read lots of your posts at Head-Fi. You are a level-headed and intelligent person. You'll do just fine, believe me.
Please keep in mind that only an idiot WOULDN'T be full of doubt and uncertainty over all of this. It shows that you are a reflective, imaginative person.
