Speaking as a woman who was on ortho-novum, you need to use a backup method if you missed more than two pills in the first week. If you had unprotected sex, you very well could get pregnant by not taking the pills. You should have received an information packet with your pills. It tells you exactly what to do if you miss any pills.
As for taking 2 weeks to be reliable, if you have been on them for a time, and you were just starting a new month's pack, you are fine in that regard as long as you didnt' miss any pills in your last active week.
It is too early to tell if you are pregnant now though. Wait until your period is supposed to arrive, and go from there.
As for a little advice-if you chose not to take all the pills, make sure you use a backup method.