Hello, You have history of having regular periods. Presently, you are experiencing delay in periods, sore breasts and stomach ache. You had pregnancy test done but it came negative. There are many factors that may cause delay in periods like anemia, PCOD, thyroid dysfunction, hormonal problems, poor general health condition, etc. However, if you had unprotected intercourse and were not on regular CP and did not take emergency CP then you may be experiencing early signs of pregnancy. You are suggested to get clinically examined by an OBGYN, get per vaginal examination done to detect bulky uterus. Your treating doctor may tell you to get USG(Uterus with fallopian tubes) to detect the gestational age of the fetus if pregnant or ectopic pregnancy. In case you are not pregnant you will be accordingly treated. You may have to go through some blood tests and investigations so that the treatment can be started at the earliest. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Nupur K., General & Family Physician