Why do I have severe stomach pain at 5 months of pregnancy?

It is good that you took a morning-afte­r pill. Brown or black discharge is normal after taking the pill. It happe­ns because the pill can change­ your normal cycle. This discharge can also happen be­cause of stress or other things. It doe­s not always mean pregnancy. But if you miss your period, take­ a pregnancy test to be sure­. 

Since you had a delay in your monthly period, it may be a sign of pregnancy, but there are other possible reasons particularly stress and changes in hormones. To know that you are safe you could do the test only after the 14th of May and learn if you are expecting. Your cycle is subject to the effect of countless factors in various states of your body.

It is common to get delayed periods but if it continues for a longer period of time the consult with a gynecologist

An abnormal vaginal bleed after menopause could indicate the presence of uterine cancer or endometrial hyperplasia and hormonal imbalance. I recommend that your mother consult a gynecologist immediately. A gynecological oncologist is a specialist who can diagnose her in more detail and prescribe treatment if necessary.

I-pill is not 100% effective and has side effects involving changes in menstrual cycles. I-pill often causes delayed periods as a side effect. I would advise seeking the opinion of a gynecologist for consultation and evaluation to exclude other latent conditions.

A faint line on the pregnancy test can indicate an early pregnancy. The black of a line you are managing could be implantation bleeding when a fertilized egg sticks to the uterus. It is a common thing in the first three months of pregnancy and it's often nothing to worry about. Watch out for it and be gentle with yourself.

Puberty can start at different ages for different people and there is a wide range of what is considered normal. 
The ability to have children (reproductive maturity) usually occurs after the completion of puberty when the reproductive organs, such as the ovaries and testes, have fully developed. For most individuals, this occurs in their late teens or early twenties. However, it's important to remember that everyone's development timeline is different.