Re: what exactly does nursing "on demand" mean?
It sounds like you're doing just right. At 7 weeks, a baby's cues are still hard to read- sometimes what looks like a nursing cue is really a "I have a wet diaper" cue or an "I want to be held" cue. As she gets older, she'll be able to give you cues that are easier to read (and you'll get better at reading them). But with a young baby I say to always try nursing first. It's always soothing, you really can't nurse too much (even if the cause of the fussing is gas or colic), often the baby really is hungry, and if she's not hungry she won't eat. She'll just spit the breast out and keep on fussing until you figure out what's going on.
Don't worry, Mama!
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!"