I’m scared

So my bf and I had unprotected sex yesterday. And he slipped it in for a few seconds after minute of cumming. I started the pill the first day of my period which was on Tuesday. Should I be worried I’m pregnant? Or does the pill automatically work if you start the first day of your period. I got my period in the morning but I didn’t take it till I got home at 9pm. Should I be scared I’m pregnant? (Btw my period hasn’t stopped)