If your are 6 days over due , then you may perform a urine pregnancy test to rule out pregnancy first. If negative, then these abdominal aches, headaches are a part of premenstrual syndrome, which indicate that the menses are due in next few days.
It is suggested that you wait for few days for your menses to resume.
I hope i have answered your query,
wishing you good health,
These Q&A’s are for educational purposes and should not be relied upon as a substitute for medical advice you may receive from your physician. If you have a medical emergency, please call 911. These answers do not constitute or initiate a patient/doctor relationship.