I took my sunday pill on saturday by mistake... should I miss sunday and continue on monday?

For some reason, the name of the medication is not listed in your post. If it is a birth control pill and it is NOT a tri phasal pill, simply take saturday's pill and then mondays on monday. If it is a tri phasal pill ( pack of pill has 3 to 4 colors of pills depending on if you are on the 21 days or 28 day pack ) and there is no color change between pills on sat and sun, simply take saturdays pill today.