Hello, You should always take CP as instructed in the leaflet at the same time every day, irregularities and throwing out affects the efficacy of the CP, this way you will be at a higher risk of becoming pregnant through unprotected intercourse. Since your breasts are sore and you had been having unprotected sex, you may be pregnant. Get a pregnancy test done with the first morning, mid stream urine. Get clinically examined by a gynecologist, het per vaginal examination don to detect bulky uterus. Your gynecologist may ask you to get done few required blood tests and USG - uterus and fallopian tubes to confirm pregnancy, gestational age of the fetus, well being of the fetus or ectopic pregnancy. You will manage or treat accordingly if pregnant or not pregnant. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Nupur K., General & Family Physician