Is it possible that I have an anxiety disorder?

Possibly. There are a number of types of anxiety disorders. The best way to know for sure is with a comprehensive evaluation by a psychiatrist or a psychologist. Medical evaluation for underlying conditions is also very important.
Anxiety Disorder. Anxiety Disorder can have •Excessive anxiety and worrying •Apprehensive expectation •Difficulty in concentration •Too many thoughts racing •Feeling on edge •Irritability •Restlessness •Muscle tension •Sleep problem Difficulty falling sleep Difficulty staying sleep Restless sleep •Waking tired •Fatigue See a Psychiatrist for Medical and Psychiatric Evaluation for Diagnosis and Treatment.