A delay of about a week like this is common and doesn't always mean something's wrong. Protected intercourse with no ejaculation makes pregnancy unlikely, but stress, travel, or a shifted ovulation date can easily push your period back too.
Next Steps
If your period still hasn't started in the next few days, a home urine
pregnancy test taken with your first morning urine will give you a clearer answer than waiting it out.
Health Tips
Please see a gynaecologist if the abdominal pain gets worse, you start bleeding heavily, or your period still hasn't come after another week.