Has anyone else this problem? And how do you deal with it? I know one is supposed to accept the sensation, and sometimes I manage, for days at a time, too, but it always returns. 

I should probably specify, I'm talking about breathing awareness. Developed that from a misguided theory and attempt to prevent myself from swallowing air or overbreathing becuase I had/have GI issues (didn't work, of course). 

But ever since I've become aware of the usually unconscious act of breathing, and it's pretty annoying. 

I've had anxiety for years, interspersed by bouts of depression. But this does feel more like OCD. Especially in the beginning of my anxiety, I've pretty much felt every waking heartbeat for more than a year, and every single one was too fast and the sign of heart attack, etc. - so there was a great deal of anxiety and panic attached to the whole sensation. 

With the breathing, I don't necessarily feel threatened by the sensation or think it's a sign of something portentous, but it's a constant awareness, and at that quite taxing - it overshadows other tasks/occupations, I often can't quite focus on reading because my attention is half directed to the rise and fall of my belly (because I've also become pretty obsessive about belly breathing instead of chest breathing - that's why most of the anxiety techniques aren't much use to me, because conscious breathing/breathing techniques aren't relaxing to me at all :)  ).