(What Aaroncort explains is perfect for someone suffering from depression, but I don't think this is the case here.)
You need a vacation. After those exams are over, don't touch a book for a week. Do something else and let your mind rest for a while.
It's essential to have a little break once in a while. Take your thoughts off of your studies every now and then, to let your brain assimilate the new information and adapt to the new situations.
Movies, books, music, friends... All of those are perfect to alleviate the stress. It would also be great if you could talk about this stuff with someone in your exact same position, like a classmate.
Turning to a headphone forum for advice is not a bad option either, as there are many people here who have been in a similar situation.
Learning how to deal with stress is not simple. Picture yourself being a car, for example. If you go top speed all the time and never stop to let the engine cool down, It'll break down quite quickly. You have to learn how to operate this car for maximum efficiency without shortening it's life-span. So letting the engine cool down once in a while is essential. As is taking care of it's other needs.
Some people schedule their activities, and it seems to work. I.e. from 16.00 to 20:00, studying. From 20.00 to 22:00, leisure activities. Weekends should be for rest.
You are not a machine, none of us is.
Keep that in mind and you'll be ok.
Oh, and life is not a rehearsal, so you might want to try to enjoy it while you can.