Hello, First of all, you should undergo one home pregnancy test to rule out pregnancy as condom has high failure rate (around 15%). Other reasons of irregular period could be PCOD, hormonal imbalance, over wt/ extreme loss, mental stress, emotional upset, eating disorder, thyroid problem etc. Therefore, I suggest to undergo one USG lower abdomen and hormone test in the absence of pregnancy. Kindly, consult with your gynecologist and take advice accordingly. Combined hormonal pill is quite effective to treat irregular period. You should control body wt, avoid stress, take healthy low carbohydrate diet with avoidance of fatty food and sleep properly. Be well.