Susan, I may have a few suggestions.

I went through a similar thing. I was not thrown but had a back problem which along with the pain and worry of falling my riding abilities went right down the drain!

First for you I would make sure that you see a chiropractic doctor, being thrown or injuring one's self always moves things around even if one doesn't feel like it does. Taking care of the medical problem is also very important.

Now for the emotional part of the problem:
If you can find someone in your area that does what is called NeuroEmotional Techinque, or N.E.T. It helps the brain change from flight/flight state. Many times we have underlying problems that do not have anything to do with what is causing the "tenseness" we feel in a paticular situation. Finding the cause of the tenseness is key. It sounds like you already know the problem. Someone who does N.E.T. will disconnect the tense from the brain. The brain is sending signals to the body to be tense because of your fear, apprehension, horse twitching you are reacting too etc. N.E.T. will disconnect that signal. You will still have the problem of being apprehensive, however you will be able to deal with it better when your body is not doing the flight/flight thing. Then once that is accomplished the horse, who we all know is a mirror of us, who picks up subtle signals deep inside us should be calmer too.
You can google NeuroEmotional Technique and find someone in your area who does N.E.T.
If you don't know why your horse threw you I would have a vet who does chiropractic check your horse. Most times pain is an un-addressed physical discomfort, something you may not even know is wrong. Check out my website : intuitiveequine.com If you have any questions feel free to email me! Good luck! Diane

Susan-

First off, I agree with Diane completely about everything she had said in her comment. Especially the chropractor part of it. One of my close friends went through almost the same thing and after she had gone to the doctor, she had gained much confidence.

Also, when you are riding in the arena, have someone that comforts you in there with you. If you have to, have them put your horse on a lunge rope while you are riding her/him. Personally this makes me relax much more too.

Sorry this is so long. But when you mount your horse, just make sure she is relaxed at first so that will make you relaxed. When you mount, just sit, take a few deep breaths and gain confidence. You can do that by just saying to yourself and (if it makes you feel better) to the horse: "We/I can do this.I am going to (set a goal)."
This allows me to relax and gain ocnfidence in myself and my horse. I am not trying to be bossy; I am just using personal experiences.

Then, take it slow.
I hope you can use this advice as I do for myself. I have been bucked off of a horse many times before and I just tell myself I am going to tell my horse, with body language and soft voice, that I, too, am ready.

Sincerely,
LeeAnn
members.horsecity.com/sca...

Great advise also Susan.
Relaxing is sooo very important! We get so much in a hurry in our lives that when we get on our horses we tend to hurry there also. I have found that being around my horses helps me to relax and slow down, they demand it of me!
And the breathing, we don't breath as it is and when in a stressful situation we hold our breath or "shallow breath". This to a horse is like the lead mare saying to the rest of the herd something is going to happen, or what is out there that is going to get me? So by relaxing first, like Susan suggested, taking a deep breath and be aware of your breathing while getting ready to mount. Also be aware of your body, relax your muscles from head to toe. Shake off the tension. Then once mounted sit and breath and wait for the horse to do that deep breath out also. Sometimes they do that snort or licking and chewing. Once they know you are relaxed they will relax and feel it too. Wait for that then move forward. When your bottom hits the saddle sit deep on your sits bones and allow your bottom to be fluid. Still have to hold yourself up, but let your bottom become fluid in the saddle. The fluidness is a relaxed state for the horse to feel. (Fluid is the only word that comes to mine! sounds funny but it works)

Horses, like people, get into routines or know people's personalities. A horse can be soft and kind with one person and edgy with another. Neither person hurts or abuses the horse but it is the humans way of being that puts the horse on edge. This is why they are wonderful animals for therapy they mirror us without judgment or opinion. This quality has allowed them to survive as prey animals for so many years. Sensing danger or tenseness in a person can, for the horse, be a sign of "danger is on it's way". Being the prey animals they are flight is their best defense. So add that to the mix of working with us humans! Horse people know this, we all know this, but being aware of it each and every time you ride can help.

I have had gone through similar experiences and with the help of MANY friends and the loving support of my horse/friend/teacher Cochese I have gotten back my confidence.

Great riding! Diane