could i be pregnant?

i stopped taking my birth control pills about a month ago and i am still sexually active. we use a condom as back up. there was a day that the condom slipped and came off. i was 3 days late on my period. the day that i was suppose to start which was on 10/14/11i had brown discharge for 3 days straight. tuesday afternoon i had ffinally started what i assume was my period.. i had very painful stomach cramp and also a little back pain. i was in so much pain that i could not stay standing for too long of a period without being in pain.. So i had heavy bleeding tuesday and wednesday which i dont feel is normal. i stopped bleeding wednesday night. thursday night and also today, Friday, i hadbrown dischage. could it be possible that i may be pregnant?