I think you'll find its reasonably common hun. I'm expressing full time for my DD and my lefty is my power boob, righty is very slow. Even when both boobs are emptied my lefty is almost twice the size of righty, just going to be the way I think for me. Our bodies are not symmetrical so one boob usually has more ducts and milk producing bits than the other. Sometimes no matter how much you even out expressing/feeding etc. there is always going to be a difference IYKWIM?

DP gets a giggle out of mine too!