Bare IUD Sex

So Monday I started my period (little bit of actual blood then some spotting). Going onto Wednesday, my boyfriend was at my house. We both got horny, but he forgot to bring a condom. Keep in mind I’ve had my IUD for about 2 months, almost 3. I went and checked my stings to make sure it all seemed good, then we started having sex. It didn’t last long and he didn’t finish, because we got interrupted. My mom called me on my phone 🙄. Anyways, do you think I won’t get pregnant since I was on my period, I have an IUD, and he didn’t even finish?