In the past, I suffered from "it" greatly. I would feel pressure in my stomach and it would almost rise to the top. It became harder and harder to breath, and after a while I would just colapse. Usually after 15mins of falling, which was basically a strong panic attack, I would feel normal. The actual hard breathing time and pressure in stomach/chest could have lasted many hours, and not always did it result in a panic attack.
It is just something I had to overcome. I know everything about myself, and I knew the reasons that I felt like that. In time, I was able to correct the majority of it.
-sk