“Anxiety is a normal emotion. It is your brain’s way of reacting to stress and alerting you of potential danger ahead.
Everyone feels anxious every now and then. For example, you may worry when faced with a problem at work, before taking a test, or before making an important decision.”
From WebMD website.
“But anxiety disorders involve more than temporary worry or fear. For a person with an anxiety disorder, the anxiety does not go away and can get worse over time. The symptoms can interfere with daily activities such as job performance, school work, and relationships.”
From the National Institute of Mental Health.
Surviving Anxiety 