I assume you have ventolin but do you take anything else? I have to take Fostair morning and evening as a preventor, plus I have to take Montelukast 2 hours before any exercise to try and stave off the exercise induced asthma. I do still get the odd attack even when I take the Montelukast, but I really do notice when I forget to take the meds!
I have for the last 10+ years have been quite lucky with asthma. I reckon it was having our house with wood and tile flooring, no carpets and the banning of smoking in public places.
It happens like clockwork in June, my asthma returns for 2-4 weeks then subsidies. I dont take meds the rest of the year. I keep an emergency stock of ventolin and steroid just to get me over this period.