OR, your leaning your body bakc and/or your rotating your shoulder up. If you have to shoot with an arm guard, rotate the shoulder down. (stick arm straight out with thumb down...this is shoulder up...rotate hand so palm is pointing up..this is shoulder down...keep bow arm in shoulder down position and rotate ONLY wrist back to vertical...had to explaine in text).
Your peep eye should be in line with your zipper. If you still have to tip head forward...get a longer draw.