Sleep is a necessary way for body to recover itself. If you do not sleep, it would be much harder to memorize knowledge, and unable to focus while studying and taking the actual exam.
Create a plan helps you to clarify your goals, distribute your time properly, and manage your workload. Most importantly, adhere to your plan!
During a long period of studying, divide them into sections is important because you can relax your brain periodically. Also, giving sometimes to play a game or take a walk will help your brain to condense and absorb knowledge.
Although you might think getting 5 in AP exam is your most important goal because it looks good on college application, also think about what have you actually learned from this subject. Try to make your goal more specific, is it straight forwardly getting a 5 or doing your best during the exam?
Teacher and adults are more experienced at managing stress. If you ever feel overloaded during AP preparation, it is helpful to talk to them and have someone to bear the stress with you. They might also help you by providing better strategies for studying and reminding you to take care of your body.
Meditate allows your brain to empty itself from all sorts of information. It is a practice for concentration. It rises your awareness of the present moment and extracts your brain from being constantly exposed to information.