Hello.. I`m going to try to make this simple and easy for you to understand because my english is not that good but will do my best.
So my girlfriend(she is 15 years old) was in another country for 3 months and she came back on the 2nd of December and we had intercourse but we used Pharmatex(vaginal spermicide)and before the end I put on a condom and came inside it.. Same thing happened every day until the 10th of December.. I checked every single condom to see if it had holes but they all we good(we used durex). So now is her 7th day of being late in her period.. It should have camed on the 6th of December but it didn't.. On the 9th and on the 11th we did two SureCheck pregnant. Tests and they were negative but I am REALLY worried so please tell me what you think :(

Condoms are not 100 percent. And many women get pregnant even using two forms of birth control.

It also may be too early for the tests to show. You may have to wait till next month to see if she misses that period also.

I suggest getting blood work done to confirm or deny pregnancy. Home pregnancy tests are not as accurate as blood work would be. It is possible she's pregnant or just experiencing an erratic cycle.