As I've mentioned before, I'm a Western rider. But, one thing I think is important is that we need to learn to ride (for several weeks or months) without reins before we use reins. That's because we need to separate our bodies from our reins. You should be a good rider without reins in order to be a great rider with reins.
Your legs are going way too far back. If you allow this you're going to fall off the horse. It's not a stable position and it's dangerous. My daughter has come off her horse twice due to this same leg position. It appears that you're using the reins to support yourself and are pulling too hard on that horse's mouth.
Please don't take critiques too personally. People don't critique you to be mean (at least not on this board). They do it to help you become a better rider.