What Causes Delay In Menstruation?

hi doc,my boyfriend i was fooling around...he fingered me,he touched my vulva...but as far as i can rem he did nt ejaculate..his penis touched my vulva..though he was very much turned on...i have gained a weight in last two months...i gt my last period on jan 31st and v wer fooling arnd in feb...i dint get period in feb...4 yrs back i had missed period for two months the same time (feb march)...i am a virgin...please help ! so confused so as to why havnt i gt my periods...