Hmm ... you know it might just be a good idea to worry a bit. Deliberately, I mean. Cultivate the worried feelings one can easily get when things like this hang over you. That way you can convince yourself that you have to make it purely on the strength of the exam, with no help from the year mark.
Considering how close that is to the true situation (even with the generous yearmark portion they've given us for this course), you're probably worrying yourself up closer to reality that way.
It all depends on how effective a motivator you find fear to be.
(Works pretty good for me sometimes)