What Causes Irregular Periods,itching In Vagina And Abdominal Pain?

doctor i had taken i-pill on 3 april after having sex with my fiance & on 13 april get my periods i.e my cycle date but next month wont get my periods but on 3 month hav 2 days periods also since then i have problem of ltticing in my private areas & little bit abdominal pain also plz kindly tell me this is due to???