Hello, You had unprotected sex. Presently, you have delay in period. You were not on any birth control pills or device. You are suggested to get clinically examined by an OBGYN. Get per vaginal examination done to detect bulky uterus. You should also get pregnancy test done with the first morning mid stream urine to detect pregnancy. Your OBGYN may suggest you to get USG (uterus and fallopian) tube done to detect any possibility of ectopic pregnancy. You will be managed and treated accordingly. Other medical conditions that may cause delay in periods are anemia, stress (emotional and psychological) and anxiety, hormonal imbalance, polycystic ovary syndrome, menopause, etc. Take food rich in iron, calcium, magnesium and protein. Take adequate rest and quality sleep. Stay away from addictions if any. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Nupur K., General & Family Physician