He didn't pull out....what are my chances?

Ok, so I was wondering what my chances are of getting pregnant since he did not pull out this time, and I'm on the pill. I already know that the pill is not 100%, but today I didn't take my pill on it's normal time schedule today, I took it later today, about an hour before it happened. So could someone please tell me what my chances are of becoming pregnant. I'm a little worried. I've also been on the pill for almost 3 months now.