Stress is the result of events or stimuli that causes disturbance in you.
These stressors bring out strong emotional responses, such as fear, anxiety, anger, hate, and sadness. Most likely, psychological stressors can only be experienced by human beings.
These events or experiences are perceived as threats or challenges to the individual and can be either physical or psychological.
A stressful event — whether an external happening like the sudden appearance of a snake on your path or an internal event like fear of losing your job when the boss yells at you—triggers a cascade of hormones, including adrenaline and cortisol, that surge through the body, speeding heartbeat and the circulation of blood, mobilizing fat and sugar for fast energy, focusing attention, preparing muscles for action, and more. It generally takes some time for the body to calm down after the stress response has been triggered.
Prolonged or repeated arousal of the stress response, a characteristic of modern life, can have harmful physical and psychological effects, including heart disease and depression. It is always good to seek counseling and guidance before stress overtakes or overrules you, as it will have a very harmful and disturbing effect on your day to day activities.