Dark brown discharge before period, had my period, am I pregnant?

Patient: I started having thick dark brown discharge on 10th march. I was supposed to come on my period on 17th march, but because I was on holiday I took two pill packs in one after the other. Even though I continued the pack, I still had the thick brown reddish discharge from 17th – 24th. I was having regular sex during this time, but still using my pill and he came out before he came inside me. But on the last day (24th) he came inside me. But the next day I stopped my pill and I came on my period and had a normal 7 day red blood period. I am now not on my pill as I decided to give it a rest. And I have not had sex since my last period. But my next period is late, and I don’t know if I am pregnant? I took a test and it was negative. Does anyone know what this could be? Am I pregnant? Please help.