I got a new bra a cup size bigger than my regular bra size and it's still too small. It looked so big on the hanger! My mom says go up a band size and down a cup size, but that seems like the reverse of what I always read to do on those sizing things (where everyone comes away wearing a 31FFF). Any recommendations?

(I'm on my way to a Dr.'s appt. so I may not respond right away. Please don't think I'm ignoring you.)