Im 18 and i had sex only once last march 23,2011 and it was protected and he didnt came inside me. I had my period after that last april 8-13. Last april 9, i went swimming and the water was very cold and i was experiencing abdominal pain during that time like dysmenorrhea which i often experience when im having my period. I was hospitalized for 4 days last april 10 due to gastroenteritis and i was on antibiotics and dextrose that time and they did not let me eat anything. I lost 3kg which made me underweight . I also found out that i was anemic . Now may 13, i still havent got my period yet and i dont experience any pregnancy symptoms. I also noticed white discharge which i usually experience before a period. I think this is the first time my menstruation is delayed. Last night i experienced a short stabbing pain below my belly button down to my vagina and it only lasted for a few minutes. I think im stressed and im not getting that enough sleep. What must be wrong?