Baby refusing breast

Help! My baby has been acting weird since we send her for vaccination last feb 17, she became crankier, doesn't sleep well at night and taking only short naps (max 15mins each) in the day. Because of that it's so difficult to feed her, she will fuss for hours while arching her back and refusing my breast when I offer even if she's due for feed. I can only feed her when she's really sleepy. I dont know what to do ?