I didn't study hard for my final I just had last Tuesday but back when I was taking similar exams my first go around in the 1960s and 1970s I wouldn't study at all and would get a "C" so I knew my fear of failure was probably "illogical". How do you "normally" do on maths? You'll probably do about the same? That's what I comfort myself with at any rate. Not a whole lot one can do about it "now" anyway if it's too late?

Best attitude I have for myself is to do the best I can while I'm there. I usually get into a rhythm and things get better after I've been working for a bit; I guess it's like sports when they talk about being nervous before the first score, etc.