3 week long brown discharge

I was suppose to start my period 3 days ago but i've been having brown discharge for 3 weeks now. I'm not sure if this counts as a period. I had cramps around the time it was suppose to start but didn't get heavier. Last month my period only lasted a day. I'm on the pill, i've been on it for 4-5 months now. I'm pretty good at consistently taking it. I don't even know what to think. Should a take a test?