Pregnant on birth control

I just had a c-section 6 months ago. I've been taking my oral birth control every day at the same time. Missed my period so I took a test to find that it is positive. Has this happened to any of you ladies? Did taking the birth control during those two weeks have an effect in the pregnancy? If I knew I was pregnant I would not have been taking it for sure. Ugh. I'm blessed but definitely stressed and freaking out a little.