Please help! Also sorry I'm uneducated about this

So I'm 18 and my boyfriend and I had unprotected sex a week ago for the first time in over a year. (He did pull out but that doesn't mean anything and I'm not on birth control. Dumb move i know..) And for a few days after I was spotting a brown color and it itched a little down there. And I was researching why this could be happening and as for the spotting its apparently common in early pregnancy? My period is also super irregular. I've had it maybe twice in the past year. Maybe I'm just being super paranoid but I'm scared. Also what about the itching what could that mean?