When should I start studying for the AP Euro Exam?

Its the middle of February and I have to take the AP Euro exam in May. I know i still have a few months but i am really scared. Im not doing that well in that cl and got a C+ for the 1st semester. im not that great at multiple choice. So anyone who already took the exam any advice? I have the Rea test prep book and princeton review and also have the sparknotes powerpack. How should i study?? Any help would be appreciated. Thanks!