Why am i still coughing?

a few weeks ago i had what i figure to be the flu... i had a cough sore throat runny nose severe fatigue headaches drowseyness ect... well everything has left except i still have a cough.. its mainly at night but also if i get caught up laughing or talking alot with someone. but its like a dry deep cough. i got over everything else 3 weeks ago. could i have gotten bronchitis or something? i dont have insurance and got laid off recently so cant really go to the doctor either