Make sure you don't have acid reflux, as it can be a cause of asthma. Find out what the city puts in your water. Both chlorine and ammonia can be used, and if they are, you will want a filter so your shower isn't gassing you with these chemical vapors. If you see they useor chloramine, that's ammonia mixed with chlorine. You will need a whole-house water filter specially made for chloramine, unfortunately. I have researched it, and the filters on your shower head don't work for chloramine, even when they claim it. It takes more time or something.
Oh yes, I think I have also read that mint is good for asthma, like mint tea. I enjoy Stash brand teas. They have one called morrocan mint that has green tea plus mint. Yum.
This is a really obvious question, but you use your rescue inhaler before you run, right? I'm sure you do, but I thought I'd ask, just in case. Anyway, I run half marathons, so my runs are usually 7-13 miles in length. I also cross-train with swimming on my non-run days. Long distance, slower running has proven better for me than faster, shorter distances. Sometimes, I have problems with my asthma, especially at night and when I run/swim. It sounds like you might be having increased asthma symptoms and should take a look at your asthma action plan. Mine says I should take Singulair for a while, in addition to the Symbicort I take everyday. That really helps until things blow over. If I'm still using my rescue inhaler at night and while I run/swim, I call my doctor to see what I should do next.
Another thing to consider is that since you took an entire 6 months off, you've lost a lot of fitness. The longer you were running regularly, the less fitness you'll have lost, but 6 months is a pretty long time, so I'm sure you've lost quite a bit of fitness. You're pace is going to be a lot slower than the pace you left off with. Keep that in mind when you're training, and be patient with yourself. It won't take as long to get to your previous fitness level as it did initially.
I'm sure you've already gone to your appointment with PT, but I thought I'd post this anyway. Maybe something I said will be helpful. I hope you get things under control. Good luck on your sprint triathlon in Oct!