I Was On The Birth Control Velivet, But 2 Weeks

I was on the birth control Velivet, but 2 weeks in I lost the pack. The pharmacy was out of Velivet so I started taking caziant from its day 1, instead of starting the caziant on the second week where I left off on the Velivet. That same week my partner and I had unprotected sex. Considering I didn't miss a pill when switching packs & they're ultimately the same thing, should I be concerned about in regards to a possibly pregnancy?