B.B.
It's extremely hard to do, but let her cry it out. It really does work! I learned the hard way that the more I nursed him when he woke, the more it became a pattern. I had to break the pattern for me to sleep. At first, I just started to go in and pat his back, but I refused to pick him up. Then I started making that time shorter each night, but he still woke up every night crying. Finally, I just started letting him cry. Each night he cried less and less. After less than a week, he didn't wake up anymore. Now he sleeps great! If you think she's teeting, give her some tylenol before bed, and use orajel. This always helps my son sleep better when he has teeth coming in.
And to answer your question about the breastmilk, it does change as your baby gets older. It amazes me how your body just knows what your baby needs! As she eats more food, she doesn't need all of her nutrients from the milk, nor as much.