Brown discharge

[Please_I_need_your_help]

I had unprotected sex and I took the EllaOne contraceptive pill in the next 12-13 hours. Everything was fine I didn't get sick or anything. I took 2 ClearBlue pregnancy tests one, about 6 days before my expected period and one 4 days before my expected period. Both negative and I got my period on the day I done my second pregnancy test which came out negative. Everything was fine. But what really worries me is that my second period is 10 days late now and I'm getting this BROWN discharge and to make sure I wasn't pregnant, I done another pregnancy test 3 days ago (negative) but I am still so stressed I keep crying all the time im going to the docs on Monday but I just wanted to see if other girls had that experience. Please help me