I missed this when it was new. Good for you for finding help!
It took me a very long time, many, many years, to realize that if I got nervous, scared, figured the horse I was riding might explode, that no-one, including the horse, would be harmed by me hopping off. I give this advice to everyone when the subject of “I can’t sit the spooks” or “He feels like he’s going to explode” comes up. GET OFF. Calm the horse. Calm yourself. If that goes well, hop back on or don’t. Do ground work or don’t. But do NOT beat yourself up for wanting to put your safety right where it should be - top priority.
FWIW, all the garbage we are fed about getting off making the horse realize that they’ve “got away with something and will do it again and again” seems to be, in my experience, a load of codswallop. What I have observed is that the more I’ve done it, the less time I need to spend on the ground before I hop back on. My current horse will give herself a giant mental reset if I hop off now. “Oh, oops. Sorry. My bad. You can climb back on now. That was a little dramatic.” I have literally had both feet hit the ground and immediately got back on. Ridiculous*, but I’d rather look ridiculous than get hurt or cause my horse more stress when I can do something so simple to help.
Other horses I’ve observed - their whole demeanour changes. It’s like they figure out that The Fear is not something that needs to be fought through by both together in an unpleasant and stressful way, but something that can be managed in a less stressful manner. Consequently, they become less fearful and braver as the months go by.
Be kind to yourself. It’s worth it both for building yourself up and for turning your horse into as reliable a mount as possible. The only thing we learn from ‘pushing through’ fear is that fear is unpleasant.
*also fwiw, I have done this in company and been ‘shamed’ for it “We’re not even 1/4 mile down the trail and already someone is dismounting.” But that was that, it was over for the rest of the ride instead of tension escalating the whole ride. Instead, we had an absolutely lovely ride. I will still dismount occasionally at that park because of MY fear of heights and bridges. Last time I was there my friend said, “Uh oh, should I hop off mine too? Is she about to play Statues and RUN?” “Nope. This is for me. She’s fine.” And I was fine by the time I had walked down the steep hill and we finished our ride as normal.