Sorry about what happen. It's always my nightmare too: something to happen before the show or clinic. :(
As for the green horse, take it very slow. It's much better to just learn a little, than try to rush and put yourself and the horse in unsafe position. I'd consider it as a new experience! :)
"Life isn't about waiting for the storm to pass: it's about learning to dance in the rain..."
"When we are no longer able to change a situation - we are challenged to change ourselves."
"How people treat you is their karma; how you react is yours."