Honestly, the best thing to do is to just relax. A trend I've noticed is that EVERYONE starts coming onto TSR before the exams. So there's often forums that are put up about exams that you're doing. So go through the forum, and maybe, every now and then, just post something yourself, as with this.
Occasionally, go through some study notes, just a brief overview. Go over anything you don't know for definite. Just, whatever you do, let your mind relax, but still keep a conscious mind of what you need to know.
You'll be absolutely fine! Good luck!