I get allergy during specific months every year. Why?

Hello doctor,

I am a boy, 18 years old. For the last three years, I am facing an allergy in which I face difficulty in breathing, coughing, and sound produces while breathing. The problem increases at night and I wake up nearly 4 to 5 times during my sleep and sit for a while. This is my fourth year when I am again facing this problem. This problem arises usually in March and April and does not disturb in other months. When I faced this problem the first time, I consulted a physician who gave me five tablets of Asthalin (one for each day) and a cough syrup. It gave me relief.

But last year, when I took the same Asthalin and cough syrup, it did not work. So my parents took me to another doctor in the city who gave me Leephylline 200 mg tablets for five days. He said that it is just an allergy that will go by itself after 18 years. He told me not to drink cold water, curd, rice, etc., when the season changes. This year I again faced the same problem but I did not drink cold water when the season changed this year. This year that doctor got transferred to another city. And when I went to buy a Leephylline tablet, the chemist said that it is not coming. He gave me the tablet Allegra M as its substituent. This tablet did not work. Then I went to consult a doctor who prescribed Cefixime dispersible 200 mg tablets. It also did not work. I want to ask what is the reason behind my allergy. Why it occurs? Can you prescribe me the right tablet for my problem? Please give me advice on what to do to get relief permanently from this problem.