J.W.
There is almost no chance you got pregnant from missing two pills because it stays in your system and it is not like you have an egg just sitting there ready to be released if you skip a pill. Yes it can trigger release of an egg but not the first day, that is why the instructions tell you to take two a day for a week, to keep a potential egg from implanting.
So far as nauseous goes your body does not react to a pregnancy until the egg is implanted so it is all in your head. If you cannot test for a pregnancy you cannot have symptoms of a pregnancy because your body doesn't know it is pregnant yet.