“Brown discharge?”

I don't take any medicines or had a medical background. I was having a moment with my boyfriend but no sexual penetration was involved. The next day, I realized I had brown discharge. I didn't think much so I let it slide. Then I realized, days after days, I kept getting a brown discharge. It's been a week now and it became light brownish. I don’t know if I have a serious infection or it's something I shouldn’t be that worried about. Can someone help me?