Hello there my 7 week old baby has had a cold for almost 3 weeks. Coughing, sneezing, blocked nose and phlegmatic chest you can hear bubbling. My Gp this week said no sign of infection and that colds can last 4 weeks. She's feeding normally but there is a slight blue tinge under her bottom lip. Do you agree that 3 weeks with no improved breathing is normal and should I be worried about the blue tinge? Thanks...