Hello, You didn t have menstruation last month, you were just spotting. You have not mentioned if you are sexually active or not. Delayed periods can be due to anemia, stress, PID, hormonal imbalance, etc. Get clinically examined by a gynecologist get few blood tests done. If sexually active get pregnancy tests done with the first morning mid stream urine. The gynecologist may do per vaginal check up to detect bulky uterus and USG (uterus and fallopian tube). It will help to detect and confirm pregnancy. You will be accordingly treated if pregnant or not pregnant. Headache can be an early sigh of pregnancy but headache also occurs due to dehydration and constipation. Take adequate amount of water and fluids to keep yourself well hydrated. Take laxatives and high fiber diet to avoid constipation. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Nupur K., General & Family Physician