I NEED HELP PRONTO

I had unprotected sex with my bf last night (it was in the moment type of thing) and I started my period then but I didn't notice until this morning. I'm not on birth control at all! Someone PLEASE HELP ME and let me know if I could be pregnant or not. My mom would scalp me alive if she found out. My bf is taking me to planned parenthood tomorrow though...but if anyone has anything thing to calm my nerves, now would be a GREAT time