Was on antibiotics for 10days right after my last period, had unprotected sex 3days before my expected period. My period was due around 21/22 of this month but there is still no sign of them 9 days later. Had terrible lower abdominal cramps for 5mins 3days ago which left me feeling tender for 3 days.I feel a slight tinge at the odd time on my lower abdomen. I have been frequenting the toilet lately but have no pain passing urine. Could I be pregnant or had an anovulation due to antibiotics?