What is this brown discharge coming from.?

I am 19 and I had un protected with my bf. And I was supposed to have my period last week. But had nothing but did have cramps. Now I'm having brown discharge it's light not heavy. What could it mean? And I did just get off medication so could that be it. I mean nothing hurts I feel fine. And this did happen once before my period a long time ago. But any help would be great!