Sleep is important too. Science and psychology say that you retain information better when you sleep on it. I know it's hard to take a break from studying, but make sure you're getting enough sleep during finals week-- you'll perform better on your exams that way anyway! Similarly, try studying for an exam (or taking it, if you can) in the room you had class in. That's also supposed to help you retain information.

You have time. Between your 4 hour blocks set aside for the actual tests and then studying on top of that, it seems like you're rushing and cramming and too busy for anything else. You aren't. Think about it this way-- yes, you have to make time to study and show up on time for your exams, but you don't have to go to class... That's a huge chunk of extra time you have to study more, sleep, eat, or relax.

Think logically. If you can't efficiently or effectively memorize information, think logically and a lot of times you can piece it together and find the answer yourself, without having to produce it off the top of your head. Don't psych yourself out because you didn't have time to drill something into your brain.

Eat. Because food (and it's important for your brain to function properly). And I don't mean run to the dining hall and bring your food back to the library. Take a 45 minute break to sit down and eat.

Your grades do not define you! This may be the most important thing I could ever tell anyone. I know how it feels to have your parents push you and to take hard classes, but remember that your test scores do not measure your intelligence!!! It's just a test score. It's easy to get too ahead of yourself, looking at the big picture: getting a degree, job, grad school, etc. At this point, just relax and take things day by day. You are special, smart, worthy of a happy life. Remember that.