Hey there! Welcome to the forum, love your username
Well, my response will probably be half advice, half moral support but mostly rambling so bear with me.
First and foremost: Moral support. I can understand where you are coming from. After over ten years of riding racehorses and going on to eventing/showjumping I feel like I know TB's like they are an extension of my own body. I've ridden more than I can remember and love them with all my heart. I just started riding Arabians a little over a year ago and thought it would be easy after all the...interesting...experiences I have had with TB's over the years.
Not so much.
Arabians are a whole different ball game. Intelligent, bold, expressive and truly brilliant. But all those characteristics can also make for a challenging ride. If it makes you feel any better, I will share with you my last encounter with the ground at the hands (hooves?) of an Arabian:
Last July I was breaking in a 6 year old Arabian gelding, breathtakingly beautiful but full of fire. We had a difference of opinion one day out on the trails (he thought he should buck before cantering, I thought otherwise) so I smacked him on the butt with my crop a couple of times. All hell broke loose. That horse went into a spinning bucking mess within an instant. When he couldn't throw me he promptly threw himself
on the ground. I kid you not. Ground is pretty hard in Texas in July too so I was less than impressed. Well I went and caught him, got back on, went to the same spot and cantered up the hill like nothing had happened. I think the horror of being struck was too much for him and he just lost it. Now a TB, with their straightforward way of thinking, will usually pull their head in and behave after being reprimanded in such a manner.
I am not saying that you shouldn't smack her if it is indeed appropriate to do so, just that in my humble opinion Arabians can be much more sensitive and almost seem offended when too much force is applied. Usually they know what you want, they are just choosing not to do it
If you find the right questions for her she will give you the answer you are looking for.
Now for the advice: One thing that springs to mind is saddle fit - has it been checked? Predictable bucking sessions are usually from a specific cause and saddle fit is often a key offender.
Also, it is spring time and some horses feel it more than others. Not an excuse by any means but it is something to be aware of.
Lastly, when you get back on, do so with a fresh outlook. Don't think about the last time you fell off or worry about falling off again. All horses have a sixth sense for apprehension in humans and Arabians especially so. Just jump back on fully expecting an enjoyable ride and you will make it so!