Your horse is gorgeous and oh so clean!
You are using the reins for support, a big no-no. This is a result of a weak base/core which is forcing you to pull against your horse to kep you from getting left behind. I would do alot more work in two point. This will improve your balance, stamina and strength. You need more strength in your abs and back.
I am wonering if you ride in a chair seat, with your legs thrust ahead of you. Or, do you sit really deep on approach. Either of these set you somewhat behind your hrose's motion, and makes you feel as though your have to throw your upper body over each jump, to keep up with your horse and coompensate for being behind on approach.
Right now, you need to focus on resting your hands on your horses crest, and firmly. You are attempting to release with your upper body instead of with your hands. You have inclined your upper body forward, but your hands have stayed stiff and back in your lap. Focus on sliding your hands up his neck, while your upper body remins still.
Throwing your upper body forward may seem helpful, but it is only hindering your horse by placing excess weight on his front.
As for your leg, it seems to have rolled back, made evident by some space between your knee and the saddle. This also leads me to believe that you ned to work on your overall core strength. Lots and lots of two point!! It will help you lots!!