I'm on the pill, but....?

I had with my husband and the condom slipped so he wound up finishing inside of me. I have been on the pill since we got married (Jan. of 07) I was on losetrin 24 fe, but switched in May because I wasn't getting a period. So my gyno put me on Yasmin, which I have been taking faithfully ever since (Around the same time EVERY day + or - 10 min.) My husband and I always "double up" on the protection with both the pill and a condom. And this is the first time this has happened to us, am I worrying over nothing or should I be concerned. PS. The first day of my last period was Nov 14th and it ended on Nov 18th