As a fellow student (computer engineering though, so I can't really speak of organic chem... just regular chem ;)).. I can totally emphasize and really wish the best for ya ^_^ After all, if it was so easy everyone would have a degree right? XD
I'm sure you'll do a fantastic job on the test :D Don't even worry about the 'what ifs', they are a pain in the butt but even if a what if happens, you'll pull through just fine :) I know it!