I'm smart... but oddly stupid in a bizarre way... explain?

OK, I just got into high school (yesterday actually) and I'm 14 and doing all the pre advanced placement, AP, advanced whatever you want to call it cles, and I've been in advanced cles since 3rd grade. I've always been a pretty good student, and elementary was always a breeze, middle school it started to sway, and I'm not feeling that well about high school. The weird thing is I'm really smart, not being vain or anything here, but I think at a higher level than a lot of students and I have a wide vocabulary, I write "clical" music with layered instruments and parts, and I enjoy writing both fiction and non-fiction books on particular subjects of interest. None of these things are involved in school, I'm not that great at math (Ok, not at all shut up punk) but I know I'm smart enough... Why don't I get math and certain stuff but can grasp some things that are way beyond my level?... I feel kinda... stupid almost...*pout*