Until today. I was the only one on the schedule to ride and I was alone at the barn except for the morning care crew. The schedule had me riding two relatively uncomplicated horses in the indoor and lunging one. I lunged first--lil' guy was pretty good for being four.
Then it was time to tack up my first ride for the day. I tried to think of any excuse to not do itm but I kept coming back to this: when Stephanie comes back, how are you going to explain to her that you were too afraid to ride one easy horse in the indoor? How are you any help as a barn worker if you can't execute simple tasks?
You're not.
I decided to do the easier horse first. Audi may be green, but she's a black mega bitch mare, which is exactly how I like them. Because she's a total bitch, I know she doesn't mind being alone in the arena (although she very seriously minds being left behind). Besides, some of her issues are similar to Izzy's, so I'm familiar with how to deal with them. I tacked up and headed to the indoor. She was good and quiet when I led her around it, so I went ahead and mounted. Lil' mare was a star. After a quick reminder, she remembered the lightness off the aids we'd worked on last time, so we started to adjust her downward transitions. Instead of letting her just drop all her weight onto her forehand and crash through the downwards, I started asking her to stay up and forward through the whole transition.
By the end, I'd say her trot/walk transition was at least 80% better. I rode for around 25 minutes and mostly felt good. When I started to get nervous, I'd intentionally relax my hip flexors and ask her for more forward. This would ease the tension she was feeling and make me more confident because she was ahead of my leg instead of ducked behind it.

Then I took her back to the barn and trimmed her face up so she'd look more like a real horse and less like a yak. Success! Mare didn't seem overly familiar with clippers, but she was sensible about introducing them and let me clip away merrily.
Overall, I feel good about today. I can't expect those feelings to just magically disappear and since I'm now riding well enough that I don't really -need- to be afraid, it's time to conquer the vestigial feelings and move forward.