help

my daughter (4months old) wont drink her milk, she's not lactose intolerant, she have this attitude of crying and not sucking without giving her what she wants like a cradle, a song to get her attention and make her start drinking, at first I thought its not that kind of a big deal because she's still drinking somehow until later on she's only drinking twice to trice from morning to afternoon, she's loosing weight and sometimes pale. i guess it all started when one time while she was drinking her milk and she vomitted then it started, like she's traumatized or what. i'm hoping for a good solution coz im scared fuor what may happen to my baby. please help me.