I am not an expert or perfect rider! Far from it! But confident with my horse.. Even when he's naughty and tries bolting home for dinner! ... Because i know him. I took the time to get to know him, i watched his body language and study his reactions. I formed a bond. I still work on this at least once a week we have a session on it. If you put a horse infront of me that i didnt know and asked me to ride it, even if it was 100% guaranteed safe, I'd hesitate to get on and id be terrified! Get to know your horse, get confident on the ground. How can you be confident on the horse if you aren't confident working from the ground? Set up some spooky objects in your school, let your horse go, watch the reactions. Save them to your brain so if you are riding and he or she is getting nervy of something you can talk to them tell them its ok, build up a trusting relationship. If you dont trust your horse and get on they will know! Trust them to keep you safe. Always praise there good behaviour alot so they want to please you. Dont spend hours thinking of what might happen, talk yourself in to it not out of it. If you have lost your confidence gain it back taking steps starting with ground work for a while, then just sitting on your horse, even if someone is holding the lead, just sit for a few minutes then get off, then a few paces in walk. Set yourself small achieveable goals so you and your horse feel good after. Feeling good is the key to going further if you feel bad every time it will hold you back. On the plus side if you never ride again you still have a horse to kiss!