Hi Doctor, My Daughter Have 3 Month Old She Refused

Hi doctor, my daughter have 3 month old she refused the breast and refused the milk, and since almost one week till now always crying and refused to eat.my sister said that supposed to put water till n4 and 4 spoon of milk bcs i put water till n4 with 2 spoon of milk. Then the baby always like want to eat her hand, is it bcs of low milk?? Thank u doctor and i appreciate