distracted eater = fussy eater?

Karlee
For the last month my 3&1/2 month old has been super difficult to feed. She's to the point where she only eats for 5 minutes before getting super upset. She pulls off the breast a lot and sometimes she'll cry as soon as I offer the breast. I've been reading about distracted feeders and it's the only explanation I can think of, but I haven't seen anyone else that talks about their baby crying so much when trying to eat. It's not because she's full, she's rapidly falling further off of the weight charts (she was small to begin with and has had a hard to gaining weight). Any other babies that display distracted eating with lots of frustration and crying?