Help! I have brown discharge but no blood?

Emma-lea

I'm 8 days late from my normal period, I'm on the Evra patch, birth control? I have my normal period symptoms, super sore boobies, poo pain feelings (lol) and super mad mood swings! I've taken pregnancy tests which come back negative? Only thing I can think is all the medication I have been on, which I stopped 4 days ago due to surgery (tonsillectomy) which I was on codeine, bucca stem (sickness medication), paracetamol and ibrufen! So Idk what it can be!? What is this brown discharge!?