Today was my first day back at work and I pumped while there. I'm pretty sure I use the right size flanges as my nipples don't rub on the plastic and pumping is pretty comfortable. However, I did notice today that the tips of both nipples were completely white after I finished my last pump of the day. What could that indicate? Suction too high? Like I said it's not uncomfortable, but I want to make sure I don't inadvertently do something to reduce my output- I pumped 3 times in a 7 hour span and yielded 3oz each time.