Sudden difficulty breathing. The case.

During childhood, I used to have frequent respiratory infection (3-4 a year). Things improved when I grew up. Over the past 2 year, I have gained weight, smoked infrequently (3-5 times a week). I have history of seasonal allergies. Over the past few days, I have been having sudden chest tightness with difficulty breathing which causes me sleeplessness at night, may last upto 3 hours. I take cetrizine with relief as needed. Lately, cetrizine has not been providing much relief. I suspect this could be due to some allergen. I suspect that my symptoms of sudden difficulty breathing could be mild asthma attack aggravated by allergies. I have associated uneasiness, fatigue and difficultly sleeping. Stopped smoking a month ago (cold turkey). I have not used any inhalers ever. No fever, weight loss or cough. No known heart conditions. Please suggest me if I should use an inhaler. Is it really asthma triggered by allergies or something else. What medication should I take in the case.