Is this a symptom?

Hi

i know you can't diagnose me over the internet but.... I have asthma and use symbicort (4x200/6) and bricanyl but lately i've started to have a strange symptom. Whenever i do anything - including walking upstairs - i start panting like an old woman whose run a marathon! My peakflow is really good (475) and its not like i can't catch my breath - it is exactly like i've been running. I've seen the asthma nurse so much lately (we had a trial of singulair) and she really wanted me to lower the symbicort though in the end we both agreed i mustn't - i just don't want to bother her if this isn't related. If feeling like this is asthma then i'm going to end up taking tons more bricanyl.

I'm not going to make myself ill, ignore a serious attack, stop taking my meds etc, I'm just trying to get a bit more of an insight into what is still a new and rather mysterious condition to me (6 months in and still learning).

I'd be really really grateful for any advice you could give me.