I am feeling cramps and sore nipples.

Hi,
Welcome to ehealthforum,
If your menstrual cycles are of 28-30 days, then chances of pregnancy cannot be ruled out as your probable fertile days/ovulation days fall during the time of intercourse. The abdominal cramps and sore nipples could be early signs of pregnancy. Look out for development of any other new symptoms suggestive of pregnancy. Urine pregnancy tests usually start showing positive results after about 1 week of missing periods. Wait and watch for your periods. If you suspect to be pregnant, or if you develop any other new symptoms, then you should consider visiting your doctor/gynecologist at the earliest for a thorough examination (to confirm pregnancy related changes/signs in body) and blood/serum HCG level test (to confirm/rule out pregnancy accurately). Blood HCG level estimation is accurate and can detect pregnancy accurately earlier than urine pregnancy tests (as early as about 11 days post conception).
Take care.