Girls, can you help me? I don't understand anything. Everything was no…

Girls, can you help me? I don't understand anything. Everything was normal, we slept well yesterday. Now it's four hours past morning. The son woke up an hour ago because he overslept, not tired at all, everything is ok, but for the second time, either vomiting or burping like water. That's why I don't know whether to worry or not touch the child, let him play.