Breast size has nothing to do with how much milk
you can produce
. To boost your milk
supply, if this is possible for you, try to feed your baby every 2-3 hours for a day or 2. Don't pump, just nurse, and this should build your supply. As the other ladies said, it is all about supply and demand. When you notice your baby wanting to eat a lot, it is probably a growth spurt. Go with it and let her boost your supply.
I know what it's like to have a big eater, my daughter was the same way.