Had period nov6th-11th, had protected sex with a condom the 15th and had brown/pink spotting the 17th for 5 days, now period is 2 days late. why?

Irregular periods: Irregular periods are one of the most common problems obgyns treat. If this is one time problem it usually resolves on its own. If this is a recurring problem you should be evaluated. There are many options available to help regulate the menstrual cycle. If you think you might be pregnant check then check a home pregnancy test. They are cheap, reliable and available at any pharmacy.

Check a test: Check a pregnancy test. If it is negative, you had a delayed ovulation. Give it another week. if you still don't start, recheck a pregnancy test. if it is still negative, you need to talk to your GYN and get evaluated.