For the last few months I have had very short light 'periods' which is not normal for me. I have just found out i am pregnant. I had sex whilst i was on the pill in October, however i was taking malaria tablets at the time which i heard after can stop the pill working. And also at the end of december (not on the pill) but i wasn't fertile at the time. When did i get pregnant, is it possible to get pregnant whilst you are not fertile? or could i have been pregnant for months without knowing?