Brown discharge

So I’m 22 years old and my periods have always been regular. A few days ago, I noticed a trace of blood in my discharge when wiping. It was so little but it was on the toilet paper. Last night again, there was brown discharge with a tiny trace of blood in it. My period is expected to come in 6 days. I am sexually active with my bf, and I know that I’m not pregnant because the last time we had sex was in August before he had to leave for a month to visit his parents and I got my period a week after he left in August. Does anyone know why this is happening to me? Is it normal to have brown mixed with reddish pink discharge a week before period is due?