K.L.
Maybe she's teething and it feels good to bite. Sucking stimulates blood flow in the gums and can make the pain come on when eating. Keep trying to feed and see how she does. If she continues to bite, say no, but then offer it right again. Then if she refuses to eat, pump and bottle or sippy cup her. Once she gets the tooth she may go right back to breastfeeding, or maybe not. Sounds like she took you serious when you told her "no".
Also, I wish someone would bop me on the nose and stop me from eating. (o: