Gidday Rotang and welcome to our forum!
SophieM has made useful points and given you links to contact.
Your post is very brave, raw and very clear - I can imagine is has taken some courage to write that. Plainly, you have great determination to control such a large, powerful animal. People like me are in awe of what you guys can do with horses. Scary!
So let's look at what happened as a temporary behaviour lapse, how to acknowledge it and recover back to your normal supergirl persona when you are ready!
It is good to see that the rest of your team? and support crew has accepted what you did as a mistake with their 'anything can and does happen' approach. It seems your disappointment is within yourself, knowing that what you did was avoidable and has caused you all this embarrassment?
I'll relate what happened to me a few years ago which is a little bit similar. I was part of an eight person team in a 100km road race. We were the hot favourites and I was the key team runner. Not to far from the end of the race I was running hard on one of my turns, when my brain snapped, my confidence completely disappeared and I started walking. To this day I am not sure what caused it but it was an overwhelming feeling about 'I don't want to do this anymore'. Huge case of panic attack under team expectations I think. I told my team mates I was sorry but just wasn't into it. They were OK on the surface but later I heard otherwise.
I struggled with that for quite a few weeks then build up my mental strength and decided to send all my team mates an email apologising for what I did. No excuses, my fault and no one else's, and how much I regretted betraying all the faith the team had invested in me. Their responses were amazing. So very supportive, I felt much much better immediately. I returned quickly to my old form and that lapse never happened again. I am so glad I was able to resolve my issues that way and so too was the team.
Where is this leading to? I just wonder if you might look at doing something similar? An email to your team mates, supporters, school buddies etc that will clearly state how you feel about what happened and how much you regret it. Importantly, don't make any excuses - then ask for their forgiveness.
I am 100% confident this will end positively.
So what do you think? Give it as long as you like, do a few edits, then when you are ready send it! Perhaps even 'test' it with a close friend in confidence.
Let me know how you go! All the best, The Bro