AM I PREGNANT?? PLEASE HELP!?

I had sex without a condom. Stupid, I know. He did pull out before cumming, however, I do know that you can get pregnant from precum. A week later I had what I thought was my period for about a day. The blood was a little brownish though and the consistency was a little thicker than my normal period blood. When my period abruptly stopped I started googling stuff and apparently you can bleed when the egg attaches to your uterus which can happen about a week after sex. Is this what happened to me? I also just recently started having sex and I know that can mess with your hormones, so could that be the reason why I didn't have a complete period?? Please help. I am scared and can not have a baby right now.