I've been having issues with my hands and wrists for a while now... since I started playing stepmania.
Now, it's come to a head. Today in school, while writing very fast to keep up with the teacher, my left hand (I use it for everything) started to hurt a lot. Well, not quite my hand, but my wrist and forearm. I could barely write at all after that.

I spend a lot of time on the computer, I type a lot (10-finger, decent but not ideal posture), play Flash Flash Revolution at really high levels (it's similar to dance dance revolution, just with keyboard and a lot faster... not good for the hands), play guitar, piano, and bass. I NEED to be able to do my typing, music, writing, etc. So of course, I'm worried. Is it carpal tunnel?

My mom thinks it's from too much computer use, but I recently messed up my wrist with an awkward fall in sports class (very large swelling for about 20 minutes), and then I spent the next day carrying very heavy furniture around...
I don't know what to make of this or how to fix it. I don't have any real pain in my hands yet, but my left forearm and wrist ache.Is this Carpal Tunnel, or some other disorder? What should I do about it?