Maybe she is picking up on your stress levels. Which probably go up when she starts fussing. Have you ever heard of a product called "MamaCalm" it is supposed to help with your stress and also calm the baby. I am using it and I have a cousin who uses it and out of the 6 new babies in the family in the past year... we have the calm ones. It may not related to the product, but it is worth a try.