Just relax...I went over some organic chem reactions...
AND MAKE SURE YOU ACTUALLY KNOW WHEN YOUR EXAM IS!!!
i kept thinking it was at 2:30 and at around 10:30 I realized that it was in fact at 11:15!!!
I freaked out like a mad animal but the ladies there were REALLY nice when I called them and told me its all ok...they understood my situation...
Take a deep breath and sleep well!
Good luck!