If all of the pills in the first three weeks of your pill pack are the same color, you don’t have to worry because they all contain the same amount of hormonal medicine. You should continue taking your pills as usual and then on the third Sunday take the pill from the 2nd Sunday (that you missed).
However, if your pills (in the first three rows) are 2, 3 or 4 different colors, it means that you are not taking the pills in the usual order. For most pills, the change causes no problems except for possible breakthrough bleeding. So keep taking the pills but check in with your health care provider to make sure.