Hi, I've Been Using The Patch For My Birth Control

Hi, I've been using the patch for my birth control , about two days ago I had unprotected sex and this week is my off week. After having sex my vagina hurt really bad which lasted for about 10-20 mins then faded into being sore now two days later I'm having really strong cramping and light brown discharge is this my period coming down or something else. I put a tampon on and much hasn't come down