Anxiety symptoms are typically a response to some kind of fear. Fears can vary from relationships and social situations, work/school tasks, medical concerns, etc. Our brains and body sense fear(s) and we may experience anxiety symptoms, which may include sweaty palms, heart palpitations, stomach aches, flushed face, and so forth. The degree to which an individual experiences such symptoms varies from person to person.
Worrying a little bit about potential situations, mistakes and outcomes may have practical uses that help us be responsible and focus our energy on those situations. For example, when people have mild anxiety about meeting a deadline at work, they may gain motivation that helps them finish their work ahead of time so that they meet their deadlines. Once the deadline is over, the anxiety subsides. Mild anxiety is not something that is concerning and is a normal neurological functioning.
When anxiety reaches a certain level or intensity, frequency and duration and negatively impacts an individual's physical and mental state, or inhibits them from carrying out their daily lives, anxiety, it most likely has become a mental health illness. For example, an individual that experiences a high level of anxiety after meeting a deadline at work and continues at home to have anxious symptoms when watching tv because they are still thinking about work. This level of anxiety becomes a source of suffering and makes life hard to fully enjoy. This is what is referred to as an anxiety disorder.
Anxiety disorders can range from Generalized Anxiety Disorder, Obsessive Compulsive Disorder, Social Anxiety, and so forth. There is a specific criteria that a mental health professional can assess to determine if an individual is experiencing a level of anxiety that determines whether an individual has an anxiety disorder or "normal" anxiety. People with anxiety as a mental illness have symptoms of anxiety that don't go away and continue to interfere with daily functioning.
If you think that you are living with an anxiety disorder or other mental illness and are uncertain of whether it is "normal" or may be something more, contact a licensed therapist to help determine if you meet the criteria for a diagnosis and whether mental health treatment is necessary. Counselors can help address anxious beliefs, rational vs irrational thinking styles and ways to cope with thoughts and feelings that are negatively impacting your life.