false positive

I have a big test tomorrowand yet I'm eerily not worried at all. i studied a smidge this evening, made a cheat sheet (the prof said we could have one) , mostly used it for converting from metric to Eglish units. It counts for 15% of the total grade, so its stil a big deal, and yet I'm not sweating over it. What is this thing, confidence? Apathy?! A gut feeling that no matter what you do you'll still be above the class curve? (I'm at like 80% right now, and the class average is like 60%, so I'm in good shape so far.) Whatever.