Re: 3 week old questions - Growth spurt??
Probably a growth spurt. But it concerns me a bit that the latch is bad enough that you feel raw. Is hands-on help from a lactation consultant, preferably an IBCLC, possible for you? A consult with a LC could help you fix your LO's latch (sometimes it's simply a matter of positioning), and also help you with pumping, since the LC will be able to tell you whether or not your shields are the right size and whether or not your pump is working as it should.
Just FYI, when supply and demand are well-matched you're rarely if ever going to feel full and you'll probably have a little more challenge pumping. Most moms start out making more milk than their babies need, and that usually means they often feel full and pump a lot of milk with very little effort. But that state of affairs doesn't last because the body doesn't want to waste energy making extra milk, and because making extra puts you at increased risk of plugged ducts and mastitis. So eventually your supply adjusts to meet baby's needs very precisely, at which point you stop feeling full and can't pump as much. And when that adjustment takes place, your baby may act quite fussy because all of a sudden she has to work harder for her meals.
Coolest thing my big girl said recently: "How can you tell the world is moving when you are standing on it?"
Coolest thing my little girl sang recently: "I love dat one-two pupples!"