Kariva and pregnancy

I have been on Kariva for about a year and was getting two full periods on schedule, for month most of this time. In my infinite wisdom, I decided to switch to the placebo pills when I got my mid-month period, as this is the one accompanied by other PMS symptoms, the period most like a real one. But then after going through a full month of pills, I didn't get a period during the next placebo phase. I have two children already and got pregnant with both at the first opportunity off birth control, but my doctor had stated to me previously that if you miss some Kariva pills it is highly highly unlikely to become pregnant. Could I be? I certainly feel pregnant, there's no denying that feeling. I wonder whether I've just totally shaken up my hormones by switching as I did, and assume this is the most likely scenario.