Plan B?!?!

So I had sex Thursday night/Friday morning at 2am. I use the NuvaRing. It fell out that night while we were having sex. We didn't use a condom, and there is a big possibility that he came in me. I lost the ring, and haven't had one in since then. Can I still use an emergency contraceptive?! I don't want to be pregnant. Also, I got my period last night because the ring wasn't in. Does that mean I'm not pregnant??