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.

Intense pain during menstruation and one week prior to it may be a symptom of endometriosis or pelvic inflammatory disease (PID). It is recommended to visit a gynecologist in order to have an accurate diagnosis

the test should be performed not sooner than a week after a missed period. But any abdominal pain or irregular bleeding should be immediate cause for alarm and you need to be evaluated by a gynecologist.
 

You might have premensstrual symptoms nothing to worry about.But if you are worried, I suggest that you visit a gynecologist for an evaluation and diagnosis.
 

Variant reasons can come up with missing menstruation, like stress, fluctuations in weight, or hormonal deficiencies that cause it. If you haven't had your period, try to watch for other symptoms that may have come along with it, such as headaches or mood swings. If you worry, it's better to go and talk to someone you feel secure with, such as a parent or school nurse, who can then show you what to do to be of better help to yourself.