Meghan, relax! Take a couple of deep breaths and relax your mind and body. If you have prepared for the test by reading and studying the handbook, you have nothing to worry about. If you have time, review the material by going over it a little at the time. Don't try to do a two-hour session; just go over an area (all, if there is time, or at least the parts that are most difficult for you) then take a short break. Grab a soda, get up and walk around a bit, etc.
As a student, I'm sure you are used to taking tests. Put all your best test-taking skills and tips to good use, like you do on the FCAT. (Or maybe that's not good advice - you may be one of those kids who totally freak on standardized tests! ) But, again, relax and try your best. You'll do fine. And if you don't pass the first time, so what? It's not a one time shot. There will be another opportunity.
Good luck. BTW, I live in Florida, too! Where I am, in central Florida, the day looks beautiful and perfect for a test! Sunshine, blue skies, and fluffy white clouds! Hope your weather is just as nice where you are.