What Causes A Delayed Menstrual Period And Stomach Pain?

my usual date is on 4th. I have taken primulut-n course for 6 days starting from 2nd of feb. i had my date on 9th of feb. In this month i havent got date up to 12th and so on 13 and 14th i have taken Regestron and stopped on third day, still i havent got the date as of now.Am feeling pain in my stomach from four-five days. could you help me what actual problem is?