I was very nervous for my test, everytime I would think about it, I'd get a weird adrenaline butterfly feeling. However, after the examiner asked me the show me tell me questions, I kind of settled in. Drove down the road and I wasn't so nervous anymore.
I made 2 mistakes, the first one made me think I had failed. It was as I was going up a hill (cross road infront), there was no car behind me, as I braked I lifted the handbreak about a fraction of a second before the car stopped and it kind of jolted. I thought after that I had failed.
The second was when he made me do a turn in the road, in a very tight road, on the second bit of the manoeuvre where I had to reverse I just dry steered, thought I had failed even more. 
Then I went the wrong way, he told me to turn onto the road on the right, and there were only 2 lanes as I came onto the road. I missed the turning and asked him what I should do, he said carry on as you think is best.
So I decided to go up a three lane dual carriageway? Which was busy, (good thing is I looked a the possible test routes on the DSA Website for my test center), I knew there was a roundabout and had a good feeling he would tell me to come back round on my self, and wah hey, he did.
I went through town and back to the test centre. I really had it settled that I had failed, but I carried on to the best I could, he told me I had passed and only got 5 minors. I was shocked, speechless. I asked about the mistakes he goes, you controlled the car, and observed well.
Even when you make a mistake don't worry, it might not be as big as you may think. Nerves are excellent you tend to work harder, and much better. Just keep observing your surroundings and don't worry about the manoeuvres as in my test I did them pretty early on, 10 minutes in infact.