I doubt it's your age. I have a friend who had similar problems - each baby got less milk - and another who has never been able to nurse her many children beyond a few months. In both cases there were some hormone issues that have prevented normal breastfeeding. How thankful we can all be these babies have milk to drink anyway and that they have good moms who recognize when supplementing needs to happen!

Whenever I've pumped (just a few times) I've never gotten more than 3 ounces; but a pump does not milk like a baby and mine have always been good and fat. Your instinct about her fussing is probably a lot more reliable than what the pump is producing. ;)

You're a good mom. Good for you staying on top of the signs and making sure that little one stays strong and healthy!