I Have Been On Birth Control Since I Was 18,

I have been on birth control since I was 18, now 25, and have always had regular periods while on the pill. This month at the normal time of my cycle I had light bleeding and brown discharge for a few hours and then it completely stopped accompanied with mild cramping. No breast tenderness but definite mood swings, light nausea and fatigue. Home pregnancy test this morning came back negative, 11 days late as of tomorrow. No previous pregnancies, normal 28 day cycle, currently on Kariva birth control