I understand that there are people who don't like driving, otherwise why would we be rushing towards a soulless future of self-driving cars. But we're not there yet, and we won't be for decades. So my advice to you - if you're a nervous driver - is that maybe you shouldn't be driving.
Let me explain.
I live in Utah. We have mountains here. Lots of them. There are wide mountain passes - like I-80 which is a six-lane motorway. And narrow mountain passes, like Huntington Canyon, which is a single lane in each direction. It's sunny, and it rains, and it snows. These are all known facts around here. This makes it all that much harder to accept when I get on to one of the narrower roads, when I get stuck behind someone doing 20mph in a 50mph zone because they either don't like the curves, don't like how narrow the road is, or don't like the drop-offs either side.
Here's an idea - if you don't like driving on those sorts of roads, then DON'T. People that do this are a danger to themselves and everyone else on the road with them.
I'm talking about this today because this weekend I went up one of the narrower canyons to go skiing. The roads were wet but not snowy and I came across a tailback of cars and at the front was someone barely doing 15mph. You know they were going slow because not only were all the cars passing them on a double yellow line, the ski buses were also passing them. Going uphill.
When I finally got to the front, the guy driving was grabbing his steering wheel so hard that he literally had white knuckles. He was pale his eyes were forced wide open. He was absolutely terrified. But he kept going. He didn't do what a logical, sane person would have done which was pull over in any of the many, many, many places that are available to do so. He didn't turn around at any of the parking areas. No - he kept crawling up the road, pissing off everyone behind him so much that we were all passing him at speed on double yellow lines.
I've seen the same in California in the mountains. I've seen the same in England in the narrow hedge-lined roads in Cornwall. I've seen the same (albeit not very often) on the Autobahn in Germany.
Learn to figure out your driving weaknesses and either do something about them (courses, training), or don't drive on roads that expose you to the things you don't like. You'll be safer and everyone else will be safer.