Hi A.,
Ah, the terrible twos! It's the age where kids start testing the waters with limits, start learning to express themselves in fun ways like tantrums, really keeping Mom and Dad on their toes! Sounds like your daughter may have hit that mark in her life. It's a tough age to start with...and then adding a new little precious one, makes it even harder on Mom.
There's 23 months between my first two kids. My daughter,the oldest, didn't want to listen, definitely wanted to insert her independence. When I had my son just two weeks before her second birthday,she was not too thrilled. Because now she wasn't the center of attention any longer. It took a period of adjustment for her to get use to the shift in dynamics. What helped smooth the way is going out of my way to include her with things and the baby. I would ask her to "help" in small ways. I would talk to her about what it's like having a new baby in the house, talk about what is was like when she was a baby. Those kinds of things. But most important, I would see to it that she would have some one on one time with either Mommy or Daddy. Giving her that little bit of extra attention occasionally really helped her feel more secure. It let her know that our feelings/love didn't change for her just because their was another person in the house. What may help with nursing...try reading to your two year old while nursing her sister. Or even pretend play with her. I used to pretend to play house with my daughter while I nursed my son. I would get her little kitchen and play household items out and then let my imagination do the rest. It helped keep her entertained while I are trying to nurse. Plus, you may find you'll be less stressed because you're not worrying about what she's doing. It's the killing two birds with one stone kinda thing. Hope that helps a little! Best of Luck! Enjoy the time with your girls!