Stress is part of our life as a healthy biological response. Our body will try to adapt to the demands by generations more energy and alertness and returns to rest and digest later.  Distress, however is draining us because it is more intense or of longer duration then we can adapt to. That is also part of life, after periods of distress we need more time to recover.
Traumatic distress is an experience that overwhelmes our nervous system. That is also part of being human, and most of the time we will recover, but it often leaves a residue of unprocessed emotions, images, impulses etc.  Trauma in essence is a memory problem where the past stays active in our implicit memory.

Stressors and stress

The stimuli that cause stress in our bodies are called stressors. The reaction in our body is called the stress response or simply stress.
Too little food, or standing in the traffic jam are external stimuli, a fearful thought is an internal stimulus that can cause anxiety and anxiety. Stress only becomes a problem if it is too often, too much, too long, or the wrong moment is present.