I have the exact same issue! I pump exclusively because my 3 1/2 year old has yet to latch and I get double the milk from one breast with 3-4 streams from one and 1-2 streams from the other. They have always been uneven in size, but now even more so since one is holding more milk!!! I assumed it was normal, but just wanted to let you know someone else had the same issue!
Haha I meant 3 1/2 WEEK old, not year old Can you imagine still pumping after 3 1/2 years if your LO had NEVER latched? Oh man, I'm not that patient.