You might also be letting your bow arm shoulder come up and in during the draw, maybe even touching your chin. Be sure to keep that shoulder low, and both shoulders inline, pointing at the target.

Stand in front of a mirror and assume your shooting stance, turn your face to the mirror, then draw your bow and aim at the mirror. Check to make sure your head is canted at the same angle as the cant of the bow, that your shoulder is down and lined up with the other shoulder. And keep that elbow unlocked!