I started developing quite a bit of anxiety/fear about road biking when I first got my road bike this summer. I took some time away but that didn't help! I ended up finding a hilly-ish route that was 8 miles. I started riding it every day (nearly). This really helped me build confidence, endurance on hills, and improvement in skills & stability. A month later and I can easily ride 30 miles (albeit slowly). I really think it helped to just do something familiar and get in a groove.