I had my last period started on 29th december and it ended on 1st of january and after that I have a physical relation with mtmy partner but now it's 3rd of feb more than 30 days but I didn't got my periods I have done 3pregnancy test they all showed a negative result. Please tell me why I am not getting my periods as in past in the month of october I have taken I pill also for 2 times does this is happening as a side effect of I pill or anything else.