Late period.

So l am usually due for my period around the 11th or 12th and we're already the 14th of March and I still haven't gotten my period. My bf and I use condoms as birth control and that's it. I feel my body as I were to get my period but nothing. My breasts are very tender/sore and I'm scared it might be pregnancy symptoms. Has this happened to anyone? At the moment I'm feeling very scared. Any comments on the subject ? What should I be doing?