My Daughter Has Had A Bad Cough For 5 Days,

My daughter has had a bad cough for 5 days, somewhat congested in sinus/nasal area, headache, a little dizzy and weak feeling. The cough is not dry but not terribly phlegmy. Today there is blood when she blows her nose, bright red, not dark but with some clots. Is the blood just from irritated nasal passages or something more to worry about? How long should I give it to clear up or go to the doctor?