my 11 year old son has been sick going to 1 1/2 weeks. He has a cough that last throughout the day, but gets worse at night. He continually has a slight fever, and feels weak. it concerns me because he us usually a kid with lots of energy, an athlete. Now he just wants to lie down. When he coughs, nothing comes up, but I can hear something inside when he does cough. I have already taken him to the doctor, but they said it wasn t anything bad. That was a week ago. What do you think?