Huge spit-ups are pretty much par for the course with young babies. Some more than others, of course. The reason they happen is that the muscular sphincters that keep food down in a baby's tummy are, like all her other muscles, relatively weak. But just as your baby's leg muscles will eventually grow strong enough to support her when she stands and her core muscles will grow strong enough to allow her to roll over, her sphincters will eventually grow strong enough to keep her meals down where they belong.
One thing you might want to try is getting 3-4 oz of water or cow's milk and pouring it out on your countertop. It's going to make a huge mess, and you will probably see that it looks like much more than it is. The point of doing this is to gauge the amount your baby is throwing up- often moms think it must be a massive amount but if they compare it to a 3-4 oz spill they realize that the amount baby spat up was a lot more modest.
Keeping baby upright after feedings and burping her in between breasts may help her avoid big spit-ups.
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!"