Exhibiting symptoms of PTSD (Post-traumatic Stress Disorder) is so common that it is now being referred to as simply SD, or Stress Disorder. A couple health practitioners I know say that almost everyone they treat has these symptoms. Stress Disorder could be described as living in a constant state of fight, flight or freeze.
If this sounds like your experience of stress, my first recommendation is to notice your thinking while feeling stressed. What thoughts might be contributing to the feeling? Could you shift that thinking into something less intense?