Because it puts you on your guard and prepares you for what is to come, a little anxiety can be a good thing. However, when normal anxiety seems to spin out of control, disrupting your daily life, you could be suffering from an anxiety disorder.
Anxiety disorders are illnesses.
The origins may be biological or related to one's life experiences. They often run in families. When you have an anxiety disorder, you may feel anxious much of the time, no matter the situation. The feelings of anxiety may be so intense or uncomfortable that you find that you begin to withdraw from activities you would usually find pleasurable or non-threatening. There are a number of types of anxiety disorder, each one with its own symptoms or level of anxiety.