Irregular period menstruation after fingered

i have an irregular period.. for example i have my menstruation on jan 20, feb 20,march 28 and it end on april 3 2008. on april 9, my boyfriend fingered me a few minutes before that, he ejaculated and wipe the semen in his hand, then few minutes he fingered me? my menstruation should be on may 2 2008 but until now im delayed for 7 days.. pls help? what is the cause of my delayed menstruation. pls answer immediately....