Throwing up

Christal

I have a set of twins that are b/g their 8 weeks old. For the past month my baby girl lyra have been vomiting all of her food it got so bad to the point it came through her nose and she couldnt breathe she was gasping for air and that really worried me. I have changed her formula 4 times I only feed her 4oz every 3 hours I sit her up after each feed and she still will vomit everything back up. I have no idea what to do.