First of all, sorry you got kicked.
I went through this exact type of scenario last year. My bruise on my thigh looks very similar to the bruise you posted, although it might have even been a bit worse (not only was I kicked, I flew about 6 feet in the air from the force of the kick).
So I don't want to kick you when you are down, because I know exactly how you feel right now. So I'm saying all these things with that in mind. BUT.......
You need to stop babying your horse. What happened is your own fault. Here's why:
My horse has pushed me around for a while
So she is the "leader" in your herd of two. And it's been long-established that she's the boss, and not you.
but it's always been small things
It does not matter if it is a big or small issue. Any signs
of disrespect are huge
and overall she has had a good deal of respect for me.
She double-barrel kicked you. She doesn't give a rats @$$ about you, much less respect.
She's had the little bad habit here and there, but nothing as dramatic as this.
Which means that all those little things
over the months you have let her get away with, has now escalated to the point where she believes she can kick you to keep YOU
in line. (Remember; she is leader in the herd of the two of you.)
This was really gotten to me and I'm done with the disrespect but now I'm nervous to correct it because I feel like I might be in danger!
You are right to be nervous. This has escalated to a point where she is dangerous and she will attack you.
My mare's hind legs were DANGEROUSLY CLOSE to my stomach/hip bone, and then to my friend (who is a VERY experienced handler)'s face but instead broke her finger.
In order to fix this, you need to have only a few select people handle your horse with full knowledge of her dangerous behavior.
This has been a total 360
Nope. Not a 360. You have just not been paying attention to the progression and have been letting her get away with small things all this time. She figures if she can get away with small things, well why not the big things?
When this happened to me last year, that it "was my fault" was the absolute last thing I wanted to hear, and it certainly didn't help my emotional distress. But you know what? It was all true. I was letting my horse's manners fall by the wayside just because he had arthritis and was getting cranky and agressive. He could have very easily shattered my pelvis, or broken ribs, or punctured my lung. I am SO lucky he simply bruised the hell out of my thigh. And I too was blind to the progression of his attitude.
You've got to nip this in the bud NOW. That's great you have a dressage trainer, but is your trainer capable of dealing with a dangerous disrespectful horse? (Not all are.)
At this point in time, I would say NO riding this horse right now. You've got to get her manners under control. Wear a helmet and a vest when you handle her on the ground too. No more lolly-gagging "fuzzy feeling" quality time with her. When you are in her prescence, she is going to work and she is going to never take her eyes off of you, because you are the boss.
I personally am a big fan of Clinton Anderson because I think he explains this well as far as what he is doing and why. But I would strongly encourage you to find a trainer that is used to dealing with disrespectful horses (if yours is not).
It is not about lunging in circles for hours on end. It is about making her disengage her hindquarters away from you. Moving her shoulder away from you. Backing up when you move forcefully toward her. Direction changes immediately when you ask. And working her into the ground if she even so tries to turn her hindquarters toward you. And you've got to be careful, because they are QUICK to get you if you aren't watching her body language or know how to read it.
Ever see how a stallion treats his herd in the wild? First he may pin his ears as a warning if a horse gets out of line. If they don't quit, they get bitten. Same way the stallion might turn his butt towards the horse as a warning, and if they don't quit, they get kicked.
Treat your horse the same. If they yield to you when you "crouch" and "glare" at their hindquarters (for example), then leave them be. But if they don't listen to your warning, you'll start tapping with the whip (much safer to have an extension of your arm). And if they don't respond to that, then they are going to get a good HARD HIT until they respond correctly. Timing is critical; that's why it is helpful to have someone hands-on help you.
Your horse's "feelings" won't be hurt if you hit them when they deserve it. But they will learn that you are leader and what you ask needs to be done. They will learn to respect you, and follow you. And trust you!
Ground work translates to riding. You'll find you have a much better and trusting riding partner, if they respect you on the ground.
So dust yourself off, get your chin up, and go be the BOSS of your herd of two. Do not let anything slide. Stay firm. And stay safe.