S.,
Its sounds like your sweet baby is in a disorganized phase. This is not uncommon and I saw the pattern clearly in my own two daughters. Think of a child's development as a spiral (like you are drawing a spring vertically on a piece of paper) The right side is the organized phase and the left is the disorganized phase. As babies develop, so much happens that we can't see. Much of this mental, psychological and attitude development causes babies and children to feel "out of sorts" and have a difficult time settling. This fussy period, by the way, seems to always occur around dinner time... after a full day of exposure to so many stimuli and the sorting and learning the stimuli triggers, it is not difficult to understand.
The good thing is that an organized phase is sure to follow.
If you observe carefully, you may notice a new skill developing... if you can't see it now it will become more apparent once she hits the organized phase again.
I saw similar behavior in my daughters as they learned to:
recognize extanded family members and caregivers
hold their heads up on their own and learn to sit up
learn to pick up items in a pincer grasp
started crawling and walking
started talking
learned object permanence
etc
We got so accustomed to this natural cycle, that we started joking about it at our house....
"Oh, no - she's learning something new - wonder what it is this time" and we would compete to see which one of us could figure out which skill was being assimulated first.
On the other hand, maybe she is just hungry.
breastfed babies have a good understanding of what full feels like and if you watch her cues, she will not over-eat.
Maybe she needs a little snack while you have dinner.
L. G