Answer:
A panic attack
Explanation:
Every once in a while, Ona feels nervous to the point of terror. This feeling seems to come on suddenly and randomly. Her experience is an example of a panic attack.
A panic attack is a psychological disorder characterized by a sudden and intense outburst of fear and anxiety which causes both physical and physiological symptoms such as increased heart rate, trembling and shaking, palpitations. Ona symptoms are those of panic attack.
