The fear of not breathing was actually the source of my panic attacks, given my history of asthma. But what's funny is, it wasn't so much that I wasn't breathing when I had the attacks, it was that I was breathing too fast. Just like you. When you hyperventilate, you may get a feeling like you're not breathing enough, when on the contrary, you're actually breathing too fast. The fast breathing might be because psychologically you think you're not getting enough air, therefore you start breathing fast to get enough air. Are the source of these attacks through physical activity and exercise? The first one I had was after a game of basketball.