If your baby suddenly refuses to feed, don't panic. Most nursing strikes end on their own -- some within a few hours and most within three or four days. If one lasts longer than 24 hours, though, contact a lactation consultant or your pediatrician to make sure your baby gets enough to eat and drink. In the meantime, try:
Getting naked. Skin-to-skin contact with your baby will boost your oxytocin levels, making you both more relaxed, which will increase her urge to nurse.
Lying with her while she naps. A sleeping baby instinctively sucks, so she may be more willing to take your breast.
Walking around while you nurse. The movement can have a calming effect on both of you.