If I am a 5'9 woman and 100 lbs on the average am I anorexic?

Anorexia is not a size. Anorexia is an actual mental disorder.

You have not given enough details. Ask yourself these few questions.

-Do you often go long periods of time without eating, or eating under the daily recommended calories for your height and weight in hopes to lose weight?

-Do you see yourself as a larger person than you actually are? Do people often tell you that you're thin, but you see yourself as overweight?

-Do you constantly count calories, how many you're consuming/burning?

-Have you lost weight rapidly, for example more than 4 pounds in one week?

If you've answered yes to any of these questions, then you may have an eating disorder such as anorexia. There are more eating disorders that you maybe want to look out for.

For example, Do you vomit and or take laxatives after a binge? Or just eating. If you do then you're showing signs of bulimia.

However, your BMI (body mass index) is extremely low and unhealthy. You're very malnourished, and you probably do not consume enough calories. Which also mean you probably don't get enough vitamins and nutrition. This doesn't necessarily link to anorexia, nor does it an eating disorder unless you are showing other signs besides eating very little.

You should go and see a nutritionist to figure out a healthy diet that works for you. Tell them about how you may have concerns about eating disorders. They are the ones who can diagnose you.