Addy,
Welcome to HealingWell and the A & P forum. I understand your fear and your anxiety as it sounds well founded.
Amenorrhea — the absence of menstruation — can happen during puberty or later in life. Primary amenorrhea describes a condition in which you haven't had any menstrual periods by age 16.
Please do make that appointment with a GYN Pysician, perhaps a female physician would be someone you would feel more comfortable with.
Remember to stay in the moment but for your own anxiety and reassurance do seek medical counsel to find out what is causing the problem. It is better to know then to worry. You can make it to the physicians, just keep telling yourself "I can do this" .
Gentle Hugs to you and again a warm welcome.
Kitt