All I can say, is I myself have been in your situation, but with time, I've taught myself to just get back up and ride. The best thing that I tell myself is that you're putting yourself on the back of a 1,200lb animal with a mind of its own, and doing it out of free will – accidents are bound to happen at some point in time if you want to keep the sport up. Just believe in yourself that you can do it, and you will excel! The best way to face a fear is head on.
Just work on the ground and get your confidence back up, then you can even just sit on her. The same thing happend to me a couple of months ago :( it is all in the mind as well, just think that everything is going to go well :)