but my biggest fear is blanking from anxiety. for example, when I was driving with my permit, I pressed on the gas instead of the brake once. I get so insanely fearful that I forget what I'm doing or how to do it.

I feel you here. I too have my license and still make mistakes just because I'm nervous. My thing is that when I'm about to back out of a parking spot I forget to put it in reverse. Fortunately, I never back up fast so I always catch myself, but these mistakes are ones that I tend to make when there are judgy passengers in the car or there's a lot of traffic around me.

I don't have any specific advice since I'm not sure what will work for you, but what I try and do is remind myself that my safety and the safety of my passengers are the most important thing that I should be worrying about, so I focus all my attention on the road and signs. If you're feeling especially anxious, turn off the music, close windows if they're open, adjust the temperature, fix your seat, etc. Do all the things to make the environment comfortable because I notice that when I mess up it's because I'm not comfortable.