Hi mummies, does this look like it is the wrong flange size? At first i thought it was too big so i got a 24mm flange, after using it for 2 weeks, i find myself having sore nipples as the side of them are rubbing against the flange. This is 28mm flange and the base is feeling a little bit sore (but not the nipple). Should i get one size up? After pumping my nipple is about 22mm to 24mm..