HELP! BREASTFEEDING

So I've been breastfeeding my son since his been born, he is 9 months now! He's been doing GREAT! But a couple months ago my boobs took a huge size change! My left breast is WAY bigger than my right! I'm literally a C CUP on one size & an A cup on the other! I NEED HELP! Any suggestions on how to get my breast back to the same sizes! You can start to really tell the size difference!