Late period and weird discharge??

Well my issue is I don't recall when my last period was. Like at all. It was either the 6th of September or the 16th. I had unprotected sex last weekend and the weekend before that, then as of a few days ago I felt cramps and now I have dark brown discharge. I'm sitting here waiting for my excruciating cramps and waterfalls of blood to come buuuut nothing yet. I put on my tracker that my last period was the 6th which means I'd be 9 days late. I don't know what to think. Any advice? I'm also assuming even if I was pregnant it's too soon to take a test?