Are you getting jitters just from thinking about the prospect of having an anxiety disorder? There are differences between experiencing “casual” anxiety, which most people feel on occasion, and symptoms that could lead to an official diagnosis.

Anxiety disorders affect some 40 million adults in the United States, which is as high as 18 percent of the population, according to the Anxiety and Depression Association of America (ADAA). When someone is impacted by generalized anxiety disorder, obsessive compulsive disorder, social anxiety or other related maladies, they experience overwhelming fear and panic that affects how they live their everyday lives.

"The distinction between an anxiety disorder and just having normal anxiety is whether your emotions are causing a lot of suffering and dysfunction," Sally Winston, PsyD, co-director of the Anxiety and Stress Disorder Institute of Maryland in Towson, told Health.

The most broad type of anxiety is called generalized anxiety disorder, but you’ve probably heard it called GAD. Symptoms include persistently having anxious thoughts on most days over a six-month period, fatigue, problems sleeping, and repeated panic attacks.

You could also have GAD if you’re experiencing near-constant muscle tension from unconsciously clenching your jaw, balling your fists, or flexing muscles throughout your body. Another result of an anxiety disorder is irritable bowel syndrome, or IBS. It is a condition characterized by stomachaches, cramping, bloating, gas, constipation, and/or diarrhea, "is basically an anxiety in the digestive tract," Winston said.

Anxiety disorders can also manifest themselves in a specific situation — like interacting with a group of people. Social anxiety disorder can occur when someone consistently feels overwhelmingly self-conscious in front of others and worried about feeling humiliated, embarrassed, or rejected, or fearful of offending someone. This worrying can go on for days.

Social anxiety can also have physical symptoms like blushing, sweating, trembling and a nauseous feeling when other people are around.

Do you have sudden and repeated attacks of intense fear? These bouts, combined with intense worries about when the next attack will happen, are symptoms of panic anxiety disorder.

Don’t forget; occasional anxiety is a normal part of life, but if panic and fear are disrupting your ability to function, it may be time to seek professional help.

Read more:

Anxiety vs, Depression: How They Differ And What They Do

Different Types of Anxiety Disorders: How OCD, Social Anxiety, And More Affect Well-Being