Chances of pregnancy. For some few days?

Cycle date varies between 5-7 days Menstruation cycle - 28 days Had unprotected sex during 4th day of period i.e (25 th feb ) I'm sure that I didn't penetrate but Im not sure whether my penis tip contains precum or not . On the same day of intercourse after 6 hours I have her unwanted 72. On 1 St March she get watery discharge and on 3 Rd March she get light bleeding and you can say in a spotting way , brown discharge it continues for two days infrequently i.e ( 3rd- 4th March). Her next period date she missed that was on 23march but she didn't get her periods . She is feeling light cramping in thighs , acne , pimples on her forehead , backache . She is expecting that her periods will come , but till now no periods and today she feels heavy pain in stomach . What to do and what are the chances of pregnancy and when to take upt or I have to wait for some few days ?