What Causes Periods Thrice In A Month?

hii.. i hv unprotected sex 2 months ago.. the ejaculation ws cmpletely outside.. i took an ipill within 6 hours. after dat i hv got my periods twice..one of dem was delayed by 10 days n now i hvnt gt my 3rd period.. is it due to ipill or thr is a possiblity dat im prgnant???plz hlp me.