Lisinopril and spring and fall

My main problem with Lisinopril is the coughing. Coughing, coughing. coughing. I will be fine for 2 to 3 hours and then start with this awful cough. People will actually turn away from me if I am out shopping and a cough begins. I presume they believe it is contagious. Sometimes I end up vomiting and I cannot catch my breath. Coughing at night is really a problem because of lack of sleep. Doctors believe my cough is due to allergies because I have post nasal drip. However, none of the medications they have given me stop the coughing. I never had this problem until I began taking Lisinopril. Lisinopril is my first Blood Pressure medication.