My little Katie is just shy of 3 weeks old and she is suddenly fussy at the breast. She's only occasionally fussy, though, and I can't find a pattern to it. She will shake her head from side to side while trying to latch on, get very angry and turn red, then sometimes latch and feed for a few moments before doing it again. This is my second child and I breastfed the first for 20 months with out experiencing this problem. Does anyone know what this may be about?