When most people say they are 'lunging' they mean that their head is going DOWN toward the ball. But, I think you are saying that your head is going forward toward the target. If so, it is probably because of a faulty pivot. I have found that good players know that they have to 'stay in front' of the club. Although there are examples of good players who do each, the most popular and best is through rotation. The other two are lifting up...the player stands up through the ball to continue to feel the pull through impact ( Peter Senior comes to mind) and sliding forward to feel the pull (players in the 70's did it with strong leg drive) and I have some friends that do it with upper body slide. If this describes what you are doing, try to 'feel' like you keep your head over your right knee and get your belt buckle to face the target at impact.