yikes. please give me some reassurance!

This last Sunday I was on my period, the second to last day... and my and my boyfriend had unprotected sex and he didn't pull out. Because I was on my period and my cycle is pretty regular I'm not sure that would result in pregnancy... I'm also getting an IUD implant this Friday, which is 5 days after we had sex. And it's supposed to work as a contraceptive within 5 days. Am I okay???