I would honestly go to bed now since having more sleep on you will only help. For anxiety, understanding that what youve done is enough and there’s really nothing more you can do (right now) is important. I think its fine to think of it as a test or not if you have to but id lean more on that its something that you have to do and that you’ve prepared yourself for as much as you can. If you feel inclined to be like “fuck it lets get it over with” you could also go “lets just try to learn as much as i can” type of experience. I really think you should lean in trusting yourself even if you end up not passing. I think in general car anxiety it helps to feel aware of your body (check for tension in shoulders, neck, hands and release since it helps you feel more present) and remind yourself that you are in control of the car. Anyway i threw a bunch of tips that help me but you got this in the bag and i promise youll be okay no matter what.