Can Someone Please Help Me!! So In November I Was

Can someone please help me!! So in November I was switched over to a new birth control and it made me have two periods then skipped my December period and I got my period in January. I've had unprotected sex in December but he told me he didn't ejaculate inside of me. So my period happened about two weeks ago by now and today I found more brown discharge than usual... Can someone please help me out?