Sounds to me like she's gearing up for the 3 month growth spurt and is trying to increase your supply. It's annoying, and only some babes seem to do this. Mine did, everytime she was about to have a growth spurt (and would thus begin to require more milk), or when something big was about to happen developmentally - like rolling over, walking, crawling, etc.
It is annoying, and uncomfortable, but it does seem to help increase my supply (I WOH FT, so I pump. After she's done this yanking off stuff for a couple days, I start to get another ounce or more at each pumping session, even though I've done nothing to change my output).
Now, it could be a sensitivity to something you're eating, and dairy or caffeine are the most obvious culprits, but it sounds to me like she's just trying to create more milk. Let her do it, it'll be over in a couple days, and your supply will be better off for it. If it's not over in a couple days, or if she's acting different all the time, or any other signs of distress, start looking at your diet.