Hello, and I hope I can help you today. I am sorry that you are so anxious about getting pregnant. I am sure you know, young lady, that there is no way you can possibly get pregnant without having sexual intercourse. A boy s sperm must enter your vagina and mix with your eggs in order to conceive. In addition, women do not start to show until at least 3 to 4 months of pregnancy. So a bulge in your abdomen, does not diagnose anything except possibly the movement of your intestines. It is also completely normal, at your age, for your menstrual cycle to not occur regularly.. I m a bit concerned about the reason so afraid of pregnancy. Are you afraid of gaining weight? Many young women have issues related to body image and you did mention that you are very thin. It may be beneficial for you to speak to a counselor at school or professionally to help you understand why you have this irrational fear. However, I do want to reassure you again, that unless sexual contact with a boy there is absolutely no way you could be pregnant. A gynecologist or your pediatrician could also help guide you in the right direction. It would also be helpful for you to tell your mother how anxious you are about this so that she may be able to support your getting some professional help. I hope that I was able to answer your question today, and that my advice was helpful. Best wishes, Dr. Brown