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If your periods have been regular, it would suggest regular and periodic ovulation (return of your ovulation/fertility after stopping with the birth control use). If you had been sexually active during ovulation time, chances of pregnancy are possible. The abdominal cramps occurring before your expected period time could indicate probable implantation. Wait and watch for your periods. Look out for development of any other new symptoms if pregnancy is suspected. If periods do not start within 10 days of expected period dates, or if you get abnormal periods, or if you suspect chances of pregnancy, 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). Be in regular monitoring and follow-up with your treating doctor/gynecologist and report any new/abnormal symptoms immediately. Take adequate rest. Drink plenty of water. Maintain healthy diet.
Take care.