Corporate-pilot's opening sentence is very true. I was so nervous before my IR test that I made multiple trips to the men's toilet during my flight panning for the test, and nearly threw up. The examiner was as polite and professional as possible, and I was still bricking it! He was laid back and said very little during the flight. They are looking for competence. If you find yourself high/low make sensible correction. Off course slightly? Same. Don't CURSE yourself, and throw dummies out of pram if something goes wrong. Telling yourself you deserve to be hung, drawn and quartered upon landing won't help the remainder of the flight. Examiner may be happy with your awareness and correction, or maybe getting back on track will result in a partial. (My partial re-test took 19 minutes to pass, from brakes off to brakes on.) They KNOW how stressed you are, and your stage of learning. Are you at Bournemouth by any chance??