When we have anxiety we can really concentrate on our breathing. This can make things worse.
You can see your Dr again and ask to be checked for allergies, which are awful this time of year, and other possible causes.
I know when my anxiety and allergies are really bad I feel like I can't breathe.
I'm about 7 weeks into all this anxiety business and have learned that the more I think about my breathing the same thing happens to me, started getting anxiety when I ended up in emergency cuz I thought I was having a heart attack, but like everyone else in here, EKG was ok and blood work was fine, but ever since then any little thing I feel around the chest area I think I'm having a heart attack, been snacking on almonds lately cuz I hear its good for you and your heart, but last week while I was eating them I thought to myself, "what if I'm allergic to them?" Then all of a sudden my heart is racing, throat felt like it was narrowing and I started getting shortness of breath, had to tell myself I'm fine, its all in your head, went outside for some fresh air and it went away, but its messed up how powerful our minds are and what it can actually do to us physically, jus know youre not alone and that youre ok, I know easier said than done, but I find it helps me when I get feedback from ppl with the same symptoms and knowing that I'm not alone or going crazy, hope this helps you out.