What does this dream mean?

It sounds to me that you are trying to "find yourself" and in doing this you are not finding good choices and are finding trouble. Your parents are worried about you (the illness) and are not feeling good about what you are doing. They try to voice this to you (the coughing) but you are not listening. Maybe it's the people you are hanging around with and the direction you are heading. Everywhere you go, it's not good or right. Look for activities after school that involve good adult support. Ask your mom to help you look for places to get involved in that are positive; good after school programs, the YMCA, boys clubs, organizations or clubs offered by the school or even ask your guidance counselor.