I wear the Bravado Body Silk bras, which come in S/M/L/XL, and span cup sizes pretty easily. You sound like a M would fit you well, with plenty of give for inflating/deflating nursing boobs. They're VERY comfortable, yet still flattering, and I've worn mine nursing, pregnant, and in between, in a size L, accomodating my 36 band, and DDD-G boobs. I can't imagine trying to get an exact cup size bra while nursing anyway....the boobs literally change a cup or more within minutes as you nurse each side.