DS, 3, has had a cough for almost 3 weeks and it shows no signs of going anywhere. He has an inhaler, not asthmatic, for when he has a cough as they often settle on his chest. Have been using it to varying degrees of success. The last two nights he has woken up with the cough and almost vomiting. This morning he has brought up some yellowy/green mucus with his cough. Should I take him to the gp?