Don't stress mate, it's a piece of piss really! I did mine about 2 months ago now and aced it, literally! Only myself and 1 other passed and he only JUST passed, the rest let nerves get to them

If i can give any advice it would be to not pay too much attention to the rest of the guys in your group (excluding the instructor of course

) I found that the others seemed to be REALLY anxious and nervous and were stressing big time about what is involved in the test and what not, when all you have to do is PAY ATTENTION to what the instructor is telling you. Don't let the other guys nervousness infect you!
Treat it just like another day riding and try to learn as much as you can from the instructor. Most of all, just enjoy it mate! Thats what it's all about after all, isn't it?