Why am I constantly coughing?

I have had an on going cough for 4 months now. Went to the urgent care about 2 months ago was given a steroid pack and tussenex. Last week went to the doctor was told she didn’t hear anything thought it might be allergy related gave me zyrtec and an inhalor. Still coughing a lot, especially at night and waking up in the middle of the night can’t stop coughing, even coughed until I threw up last night. Wake up sweating and with a headache. Also I have an ionic air purifier in the bedroom. What else can I do? What’s the matter with me?
I have had an on going cough for 4 months now. Went to the urgent care about 2 months ago was given a steroid pack and tussenex. Last week went to the doctor was told she didn’t hear anything thought it might be allergy related gave me zyrtec and an inhalor. Still coughing a lot, especially at night and waking up in the middle of the night can’t stop coughing, even coughed until I threw up last night. Wake up sweating and with a headache. Also I have an ionic air purifier in the bedroom. What else can I do? What’s the matter with me? BTW I am not a smoker and never have.