Menstrual problems, could i be pregnant?

In september of 2007 i started taking yasmin. in june (2009), i started taking ortho tricyclen but then switched back to ocella (yasmin's generic) in the middle of september. since september of 2007 i have been on a contraceptive pill. however, my period started on 10/22 this thursday but was very spotty. this isn't unusual for me. however, today, friday, my period stopped (it usually lasts three days). I am on the placebo week. I also had on wednesday the 21st but i believe the condom might have ripped. Could I be pregnant? I took a pregnancy test an hour ago but it came back negative...what do i do?