Sit her upright and keep trying to burp her. Let the milk stay down for a while before putting her down. Sometimes if vomit, one of the reasons might be because of overfeeding as well. Mine gave me projectile vomits for about 5 times before I learned that I overfed her with too much milk and feeding time was also too near.
Sit upright and try to burp baby until your baby really burps. When you don't burp properly, baby will vomit or will have a stomach ache and become cranky.
Nikki Tan