Why Can't I Focus?

I take my USMLE Step 1 exactly 2 weeks from today. I have been pretty good about being productive and staying on task. I have two more organ blocks to review before I do my final "memorize everything under the sun" thing the last few days before the exam. For some reason, I am having a lot of difficulty getting back into things today. I think part of the reason is that after about 2.5 weeks of being quite productive, I am just sorta bored with the whole studying thing. I guess I feel like my score is going to be in a certain range no matter how much I do between now and the exam. I also think a lot of it depends on what form I get and how well I know that particular set of questions. If it is heavy on Micro, then I may be screwed, but I have Path, Pharm, and Phys pretty much down cold. I guess I figure that taking a few minutes to post here will kill my boredome long enough for me to regain focus on my studying.