I passed mine in January, and like you, I’m well able for most things unless I know someone is watching - then I look like a baby deer trying to walk.
I chatted with my tester throughout, ended up talking about his kids and having a laugh about general life stuff. I constantly checked my mirrors and before the test, did a run through of the test routes. My BIL took me out the night before and we did a whole overview of my car. What button does what, where’s the oil, etc? He taught me how to parallel park for the FIRST time before my test.
During the test, I just acted like I was driving with my instructor. Pretended it wasn’t a test.
At one point, I wasn’t sure what to do so I said so like I would have in a lesson. The road markings were so faded and cracked, the tester understood my hesitation but obviously couldn’t help me. My instructor had always let me make my own choices, so this didn’t throw me. I trusted my intuition after looking around (no cars coming, but cars behind me waiting to go) and took the turn. After I did, my tester said “good intuition”.
I found being completely honest and being able to laugh at myself made me feel so much better. My tester had a bit of a jokester personality too, so we got along really well and it put me at ease. Whenever I got nervous, I reminded myself that if I failed, nothing would change. I’d still be a learner driver, and would just take the test again.
Even when the test was over, and my tester was joking around with me about the result (he was dragging it out for his own fun), I felt that even if I failed, I’d be upset, but I’d live.
Bit of a ramble but basically, take the pressure off as much as you can. You’ll survive either way