Alot of women can spot during pregnancy but women dont feel symptoms until 2-4 weeks after period is due. And you confused me a little bit...You had sex a month ago during your period. And your period was two weeks late? The only thing you can do is if its really light then when its done, take a pregnancy test. Sore breasts are also due from a period, not just pregnancy. Take a test to be sure, then take one a few days later to be positive. Good luck let us know the results!

How old are you? And second of all, do you want a child?

Sounds to me like you are two weeks late and having clear symptoms. Time for a test my dear!