Pregnant..??

ok i have been off bc for 3 months or so....last sunday me and my fiance had he came in me(we were planning on starting a family because he leaves for iraq in january) anywhoo something happened now and we split up....i dont know when my last period was or i cant remember because it has been being irregular so it was maybe around mach 9 or so....so what r the chances of being pregnant? and when should i be able to test and see