Asthma and quick breathing at the end of class..

Bikram has allowed me to get a cardio work out without having to take a ventolin or a steroid inhaler before exercise for the first time in my life. This has been hugely empowering for me, as knowing there a limitation in your breath and having to rely on medication bred fear in other areas of my life and certainly tightened muscles all over my body. Initially, I only did the ‘quick breathing’ movement at the end of class very mildly and then as my confidence increased and I felt more empowered in my breath, I tried to participate fully and aimed at dispelling all of the ‘stale’ air, with quick inhalations…I am noticing now that if I go in the evening over night I will have mild asthma as it feel as though the areas of my lungs that I have not been using regularly are being purged and therefore triggering asthma – this would be ok if I felt as though I could breathe through it, but unfortunately I feel I need to take ventolin and or a steroid as obviously not being able to breathe with ease is uncomfortable. I am wondering if I am doing the right thing? And if other asthma suffers find this also and if there are any suggestions?