PKU is abnormal

Brenda • I’m 31, Art and Drama teacher, and expecting our third baby 🙏
Got a call today that my 2 week old baby had an abnormal PKU result and we have to do another test... 
Please help! I'm so worried I've been crying all day .. What does that mean? Is she going to be ok? What effects can this have on her... Anyone that has gone through this with any of their kids? :( am I just going crazy?