I suspect that you may possibly have a foremilk/hindmilk issue also called "oversupply syndrome". That happens when the baby gets a lot of the initial watery "letdown" milk, gets full quickly, and does not consume a lot of the fatty "hindmilk" that comes down after the baby has nursed for a while. It's also consistent with what you said in your other post about her popping off after a few sucks!
The great news is...if this is in fact what is going on, you have lots and lots of milk, no undersupply issues for you!
Here are some links:
http://www.breastfeed-essentials.com/toomuchmilk.html
http://www.llli.org/FAQ/oversupply.html
Unfortunately lots of pediatricians, while great docs, are not so great as breastfeeding counselors. As long as your DD is well hydrated and gaining weight and has no other medical problems, I really suggest you find a great LC, or my favorite helper, a La Leche League leader, who can work with you and offer you personalized suggestions that will help!
Best of luck!