What does my discharge mean??

So I had sex around the time of ovulation (unknowingly) and the guy came inside me. I took a plan b the same night and about six days later I had what appeared to be an earlier than normal period.. I was still having sex after this time and the blood seemed to have stopped. Now a total of 13 days after taking the plan b and 3 days post “period” I have some itching in the area and dark brown/purple discharge?? and the color has been changing throughout the day. Earlier I wiped and it was a bright red then now it’s a dark color… I know it’s a lot going on, but any feedback is appreciated!

Also good to mention I’ve taken two pregnancy tests and so far they’ve been negative, but I’m going to wait closer to my predicted period which is in two days