What kind of problem do I have? Been coughing and can't breathe when I cough.?

Okay, I've had this cough for 2 weeks now where it was dry at first but now it's feels like I have phlegm. It happens about twice a night and twice during the day. During these coughs, I can't breathe and they last for about 30 seconds. I just don't know whats wrong and I'm worried about having a cough THIS LONG. Does anyone know what the problem might be? I thought bronchitis, but I don't know if not being able to breathe is a symptom. So...?