Human body is designed to handle challenges and when this ability of the body is exhausted, we experience stress. Everybody experiences stress at some point in their lives.
Stress responses help your body adjust to new situations. Stress can be positive, keeping us alert, motivated and ready to avoid danger. The positive stress that encourages individuals to perform is called eustress. But stress becomes a problem when stressors continue without relief or periods of relaxation when it is called distress.

Here is a simple scale to measure your stress level.