Period due date was 26th and still no sign...

Hi,
Welcome to ehealthforum,
If you had taken emergency contraceptive pill within 24-48 hours of unprotected sexual contact, it should work in preventing pregnancy (provided you were not sexually active without protection after taking it). Since the emergency contraceptives contain high doses of hormones, these can disrupt the normal hormonal and period pattern causing period/bleeding abnormalities and appearance of new symptoms. Wait and watch for your next periods which can be delayed. Look out for development of any other new symptoms if pregnancy is suspected. If pregnancy is suspected, or if you miss your periods, or if you have abnormal periods, or if periods do not start within 10 days of expected period date, consider visiting your doctor/gynecologist at the earliest for thorough examination (to confirm pregnancy related changes/signs in body) and blood/serum HCG level test (to confirm/rule out pregnancy accurately).
If pregnancy gets ruled out, and if you are not ready for pregnancy, but intend to remain sexually active, you should consider visiting your gynecologist to get started on suitable regular birth control measures to be protected (after your periods). Be regular with birth control use as instructed. Avoid having unprotected sexual contact. Avoid repeat use of ECP. Be in regular monitoring and follow-up with your treating doctor/gynecologist and report any new/abnormal symptoms immediately. Drink plenty of water. Take adequate rest. Maintain healthy diet and lifestyle.
Take care.