Is it where you feel like you're never taking a full breath, no matter how deeply you breathe? I have that too, right now in fact, and I find I'm having to yawn all the time to get a full breath in. It's horrible, because it does make you panic and think 'what if I have this or that respiratory problem?', but when the doctor listened to my chest a few weeks ago he said there was nothing. I can feel mucus on my chest, though, so I'm wondering if my chest infection from earlier in the year has come back and is exacerbating the issue.
It is really, really horrible so I do sympathise with how you're feeling. You always worry in case you can't breath in enough oxygen, which can make you panic. But I am resigned to the fact that it is probably anxiety-based.
Maybe it is time for both of us to get some therapy? We can't keep living like this.