For the last like half hour my baby has been throwing up pretty much all the breastmilk I have given him. I burped him right after feeding him and he did burp really well. What worries me is that he gets very upset and like retches and gaga and then throws up a lot of what defiantly is breastmilk and some flem with it. There's just so much coming out within the last half hour and it really looks like someone vomiting with all the gagging and the fake vomiting people do. He's doing all that and I've watched babies before and I know what spit up looks like when happening and this looks painful and not spit up. Please help I'm worried for my son. Oh and he's almost 3 Weeks old