WOW! I can relate also! I use to ride anything! The ranker the better for me, lol. I even rode a bull once but all of that changed with a green horse that learned to rare up and fall over backward on me. It didn't bother me at first but I sold my horses and went about 3 years without riding. Then the anxiaty started........ PTSD maybe?? Anyway, I have a nice gelding that I am working through my fears with. He is young and we did the basic ground work and saddle work but I never left the pasture with him. He has NEVER BUCKED OR RARED UP including the first time he was saddled and sat on......NEVER, lol. I sent him to the trainers a couple of weeks ago because exposing him to trails is out of my comfort zone. When I get him back I KNOW I will be afraid of what he might do if he sees something that scares me, lol. But my love for horses will force me to work through this. It is either that or give them up wich I refuse to do. A hint for you is to take your time. If you find your heart racing, focus on that and force your body to relax. You will see a change in the horse. The better you do, the better your horse will do as he feels your anxiaty. Fake it till you make it.