I would suggest slowing your horse down with your body in addition to your rein aids. It causes you to have a deeper seat, so that you should also be able to stay anchored in your saddle better as well 
Meanwhile, maybe you should work on getting back to the basics in your training so that your horse listens to you better.
Good luck!
Meanwhile, maybe you should work on getting back to the basics in your training so that your horse listens to you better.
Good luck!