When I was on my birth control last month I forgot to take it for four days in a row, which made me have my period a week early. When I was finished my period my gyno switched me to a stronger birth control pill called Apri. I have taken those pretty consistently with a few times when I just forgot to take one pill, but I took two the next day. I am 4 days late for my period, and I am sexually active. I took a pregnancy test and it was negative. What's happening to me?http://www.saintraymond.net/wp-content/uploads/2009/12/help.jpg