Stand up straight, you are leaning way back,and get your body and shoulders square with each other. I would also shorten up the release so you aren't having to extend your finger to reach the trigger. Lower your release hand , it is causing your arm to be very high above your shoulders. Your body should literally look like a "T" at full draw.

Also shorten the peep tubing so that it isn't so tight that it is bending your string at full draw and so it doesn't break and pop you in the nose or eye.