thanks ladies you were very helpful :-)
If you didn't use protection of any sort or the condom broke, it is a possibility. However, your breasts can become very tender at any point in your cycle depending on hormone levels, even if you've never had it happen before. You would be more than far enough along for a pregnancy test to give you a correct answer. It's been nearly a month, and most are made to detect two weeks in. If you don't get a period, your doctor can also give you a blood pregnancy test, but chances are, the HPT will be enough this far in when hCG levels should already be high enough.
Its very much a possibility but you cant go based off of that. The reason why I say this is because your breast can get very tender as well when you get your period. Take a home pregnancy test (dollar store ones work perfect if you don't have a lot of money) please remember some times it may show negative if your not far enough along and if your levels are low. If your worried and a test doesn't come back a positive within the next couple of weeks go to the doctor. Especially if you don't get your period when you are normally expecting it.