What Causes Swelling In The Vagina Post A Sexual Intercourse?

I had sex with my boyfriend for the first time on the 25th of June. We didn t use protection but he pulled out. I got my period 3 days later but it was a day late. The next time we had sex was July 9th and used a condom. We had rough sex, and when I left his house I felt sore. The next day my right side of my vagina was swollen and hurt. It hurt when i peed. The next day i started to get a brown chunky penut butter looking discharge everytime I looked down in my underwear when using the restroom. I m very scared and cannot get pregnant because I am still a teenager. please help.