I have the same problem at the moment.. well for the last 12 months I would say. It's gradually improving but the only thing that has helped is riding. I still get big time butterflys when I think about riding but if I make myself get on, even for just 15 - 20 minutes, I feel unbelievable after and want to get back on again.
It doesn't seem to matter how much you talk about it or try to logically work it out, you still have those nerves. I wish you the best of luck, get on over and over again and eventually you will find you have beaten the nerves.
I have huge confidence issues. They come from being a nervous person to begin with, combined with recently leasing a horse that was just too much for me to handle.
I have since switched barns (and disciplines) in an attempt to start over. I am riding an intermediate level horse who is pretty dependable but not bomb-proof either. My confidence is slowly coming back.
I truly think it just takes time in the saddle in comfortable situations. Don't push yourself to do more than you're comfortable with, you'll know when you're ready to take the next step, and the next step after that.
I lost my confidence when the horse I rode when I was 11 called Cheeky was gone the next time I came out. I had asked if I could lease her 7 times only to come back and find her gone my riding lesson teacher said someone had leased her after I had asked 7 time, So that is how I lost my confidence
Yep it would be good to know how you lost your confidence. But a generic way of helping you out, go have lessons on the quietest old plodder you can find. Get the instructor to put you on the lunge for a few lessons so that they have control of the horse and you can just take the time to enjoy the sensation again. From there, get the instructor to put a blindfold on you, or take your reins away so you can rely on the reins to grip. May be scary the first time, but you will come away with the biggest smile on your face and have so much more confidence in your own ability to even just balance :)
Perhaps you thought the riding instructor viewed the other rider as being better, or that you weren't good enough? Are you eleven now?? Did your parents speak to the riding instructor about leasing the horse? If they didn't then there is the possibility that the instructor didn't take you seriously.
I think it would be best to continue riding to bring your confidence back up. It must have been sad to see your horse go to someone else, but it gives you the opportunity to ride other horses and experience different things.