Sore breasts and lower stomach are symptoms of being on (or about to come on) your period. Yes, you could be pregnant, because the pill isn't 100% effective and fail safe even when you use it effectively. You should take a pregnancy test to find out for sure.

U PROLLY R........MISSED PILL, UNPROTECTED SEX.LATE PERIOD...... U DO THE MATH HUN! WELL ACTUALLY THESE R ALL THE SYMPTOMS: * missed period * proof (positive test) * sensitivity to scents * repulsed by or craving of certain foods * basal temperature remains high * tender or swollen breasts * abdominal cramping (feels like menstrual cramps) * hormonal skin changes (acne, dryness, etc.) * feeling like your abdomen is bloated * more frequent urination * uncommonly fatigues/exhausted * nausea * dizziness * morning sickness (which can actually happen any time of day or night) * moodiness/irritabliity * heartburn * constipation * low back pain * implantation bleeding BUT LIKE PEOPLE HAVE TOLD YOU, EVERYONE IS DIFFERENT, BUT ONE THING THAT REMAINS THE SAME WITH ALMOST ALL WOMEN, IS, THE FIRST SIGN OF PREGNANCY IS A MISSED PERIOD....I DONT MEAN IT WAS SUPPOSED TO COME TODAY AND COMES TOMORROW, IF IT U R LATE AND IT STILL HASNT CAME....BY THE TIME ITS BEEN 2 MONTHS AND IT STILL HASNT RETURNED, THATS A MISSED PERIOD, BY THEN (AFTER 2 MONTHS WITH NO PERIOD) U GO TO THE DOCS AND TAKE A $50 BLOOD TEST, HOME TEST DONT WORK SO DONT WASTE YOUR TIME AND MONEY ON THOSE.. BUT YES THE FIRST SIGN OF PREGNANCY IS A MISSED PERIOD.... THEN IF ITS BEEN GONE FOR ABOUT 2 MONTHS, IF UR ACTUALLY PREGO THEN THE SYMPTOMS WILL KICK IN, THEN GET CHECKED! I HOPE THIS HELPED

Could be. That's what happens when you don't read the instructions or follow verbal instructions or ask questions or use back up protection... 18 years of child care and child support happens.