Hi So I've Been On Birth Control For Over A

Hi so I've been on birth control for over a year now but my fiancé and I wanted to start having a baby. But for the past three months I haven't gotten my period. So a week ago I stopped taking my birth control and we've been having unprotected sex. Friday I bled only alittle and it was brown and it stopped last night. Which isn't a normal period for me. Any ideas what is happening ?