Could I be pregnant?

Hi everyone! I had unprotected sex 5 days ago and 2 days ago I started light bleeding. It wasn't heavy enough to be my period (due next week) the color was dark brown and smelled like blood. I also wiped later on that day and had clear discharge with a little light pink in it. They both come and go and now today I'm getting light brown discharge. I'm nauesous, my boobs are having sharp pains, my lower back aches and I'm cramping lightly. I'm on BC and I take it everyday but not at the same time. Never had this happen before a period so please tell me what your opinions on this are! Thanks!!