While BF both of mine, it was clear that my right breast produced more than my left. According to the LC I was seeing for DD, it's very common and not something to worry about. If you wanted to try getting a little more out of that one, you could also maybe try offering that breast more than once. At the beginning, when DD was having problems with weight gain and my supply went to hell, I was doing 4 boobs every feed. So maybe try starting with the left, then the right, then back to the left again? I know that's easier said than done though if you're LO isn't interested. Good luck!
Oh, and keep in mind fenugreek might not do anything, as it doesn't work for everyone. I tried it and it didn't help, so I ended up on domperidone. If you are going to try it, the LC told me to take it along with Blessed Thistle.