A couple of things. If you really look down like that when you squat you will lose lower back position at the bottom. If you turn your feet out that far it becomes difficult to created the torque in your hips necessary to keep your lower back in position. I also feel the times you stopped higher you were just below parallel which is all you need. Don’t get to caught up in going ass to grass. It is hard to see your breathing but if you are taking your breaths before you descend into your chest and not into your diaphragm and abdomen, you will lose spine position at the bottom of the squat.