Could you have a friend or family member expose her to some of the things that you are afraid of in a safe environment. Maybe when you see how she reacts to those things, you will have more confidence?
I used to have a dangerous mare and I would ride alone in an arena all the time with no one on the property. I used to leave my cell phone by the gate because I worried about falling on it and breaking it, and I hoped I would always be able to at least drag myself back to the gate. So I do understand the fear you feel.
But when a horse spooks or freaks at something the most important thing you can do is stay calm and in control. Your fear will cause your horse more.