What would be another reason for a missing period?

How come your not pregnant? If your having , then of course you have a chance of being pregnant, and you listed most of the reasons for a missing period and even you said you don't fit into any. So? What you can do is take a pregnancy test, better safe than sorry. I don't want to say your pregnant, but if your having , and your missing a period. Then what? You could be pregnant, just test and see. Your 17, around the age I got pregnant with my son Aereon. Good luck. I wish the best of luck ♥