Re: creating bad habits??
No, absolutely not. As the PP said, babies nurse not only for nutrition but for comfort as well. You might think "Oh, that's going to turn my baby into an adult who eats whenever she's upset," but that doesn't seem to be how it works. Breastfed babies are much less likely to grow into obese children/adults, so whatever habits your baby is forming now are good ones for life!
Could feeding her when she's that agitated be creating bad eating habits for the future?
A baby who is nursing for comfort gets very little milk compared to a baby who is eating because she's hungry. A baby who is hungry sucks hard and deep, and stimulates mom to let down big gushes of milk. A baby who is nursing for comfort sucks slowly, shallowly, and gently, and gets a tiny trickle of milk. This is different from a baby who is feeding from a bottle, which sends forth a fast flow of milk regardless of how the baby is sucking. That's why bottlefed babies can be overfed, but breastfed ones can't.
I'm afraid that she's tired and overeating because she's eating for comfort if she's frustrated and tired.
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!"