Help please!

Kailey

So I had unprotected sex on the last day of my period (October 21st), and he didn't cum in me, he pulled out. I know you can still get pregnant from that, so I took Plan B the next day. Novemer 2nd I took a pregnancy test at the planned parenthood near me, and it was negative, then I got the Nexplanon insert that day. Since then I've been having brown discharge and with blood on and off, and I wasn't sure what that meant. I know brown discharge happens, but I am just nervous. I have been cramping and feeling nauseous, but that always happens with my normal period.