Is failure justified? How long should we wait now?

I failed my practical exam today because the examiner judged three things as serious errors that actually weren't:

Firstly, I had to park sideways on the right-hand side. I was so nervous that it took me three attempts because the first two times I thought I was standing on the curb. It was a flat curb, which I had never practiced in driving school before. But it was all right. Then, when I saw the curb between the door handles, I steered left, but not all the way in because the car was already almost straight. Then I drove forward normally, everything was perfect, the car was standing perfectly. He considered it a serious mistake that I didn't turn all the way to the left.

Then I was supposed to turn around. Stupid kid, I obviously didn't think to find a spot on my side because I was so nervous. So I drove forward into a driveway on the opposite side and then reversed out again. At one point, I had to back into the driveway because cars were coming from behind. One car also wanted to let me through, but I let it go. According to the examiner, that was a serious mistake because they supposedly hadn't noticed me…

And the third serious mistake was that when I stopped at a stop sign, the handbrake was suddenly engaged, preventing me from driving. I tried it twice, and the car kept skidding. Then my driving instructor offered me some help by asking me why the car wouldn't move, and then I figured it out myself.

Everything else went great. I signaled, my speed was okay, I observed right-of-way and right-of-way, and I checked my shoulder. The test wasn't canceled either. My driving instructor even smiled at me and, as we were driving to the MOT and the examiner got out for a moment, told me that I'd probably passed. And then the examiner said everything was fine, but I can't let you pass because of the U-turn, because you didn't turn completely to the left when you parked, and because of the stop sign.

Is that justified? And how long should I wait before continuing? Or making a new appointment? Today completely killed my motivation, and even my driving instructor doesn't know what else we could do in the lessons besides practicing turns, because I can basically do everything…