If you are practicing and start hitting bad shots then step away from the ball and work on re-establishing solid contact with a few bump shots in order to get the feel for center clubface hits
Hitting the ball fat tends to come from either falling backward on your backswing or overusing your hands and uncocking your wrists too early
Impact position is the most critical point of the golf swing and you must understand it is not the same as address, the correct impact position is how you compress the ball, get backspin and achieve your desired ball flight