Worrying about become pregnant...

My boyfriend and I had sex for the first time without a condom today. We didn't have enough time to grab one in the other room. So we just went without but he took it out before anything came out.. He said that nothing got inside and that he pulled out just in time.. But I'm scared. I'm not taking any pills. Is there a way or something I can do to make sure I won't get pregnant? If I do, I'll be kicked out of my house...