Coughing

Hi, i am 32 weeks pregnant. And i have been coughing from past 3-4 weeks, but i am absolutely fine during the day!! The coughibg starts at middle of night!! Though its not regular, its twice a week or some weeks are just fine. Taking honey, lemon humidifier. Now started taking cough syrup prescribed by dr. Anyone else having this issue? Or any experience!! Pls suggest..