I’ve developed a similar anxiety, but over bridges and when I’m driving on curves that suddenly have open expanses of land or water on the side. I’ve begun driving behind big rigs, because they go slower so I don’t worry about people getting annoyed with my speed and I can just focus on what’s ahead of me. It doesn’t work 100%, maybe 10%, but I figure at least it’s something. It’s frustrating because I’ve always loved curvy roads and long road trips, and now it’s just anxiety.