The difference between normal worrying and generalized anxiety disorder is that the worrying involved in GAD is excessive, intrusive, persistent and debilitating. With normal anxiety:
1.Your worrying doesnt get in the way of your daily activities and responsibilities.
2. Youre able to control your worrying.
3. Your worries, while unpleasant, dont cause significant distress.
4. Your worries are limited to a specific, small number of realistic concerns.
5. Your bouts of worrying last for only a short time period.
However, with Generalised Anxiety Disorder
1. Your worrying significantly disrupts your job, activities, or social life.
2. Your worrying is uncontrollable.
3. Your worries are extremely upsetting and stressful.
4. You worry about all sorts of things, and tend to expect the worst.
5. Youve been worrying almost every day for at least six months. Most people with GAD experience a combination of emotional, behavioral, and physical symptoms.
Emotional symptoms
• Constant worries running through your head
• Feeling like your anxiety is uncontrollable
• Intrusive thoughts about things that make you anxious; you try to avoid thinking about them, but you cant
• An inability to tolerate uncertainty
• A pervasive feeling of apprehension or dread
Behavioral symptoms
• Inability to relax, enjoy quiet time, or be by yourself
• Difficulty concentrating or focusing on things
• Putting things off because you feel overwhelmed
• Avoiding situations that make you anxious
Physical symptoms
• Feeling tense; having muscle tightness or body aches
• Having trouble falling asleep or staying asleep because your mind wont quit
• Feeling edgy, restless, or jumpy
• Stomach problems, nausea, diarrhea.
Note: If youve struggled with anxiety and fears your whole life, its likely that your anxiety symptoms are due to GAD; if your anxiety symptoms are relatively new, this could be a sign of a different problem.
Source: http://www.helpguide.org/mental/generalized_anxiety_disorder.htm