Ditto as Mitch82 said,,,,,,,,, Remember for next time,,,, The best friend of a girl is a Condom,, Not her Boy Friend,,, always keep it between you and him until you know his status accurately
Unprotected vaginal sex is a risk of HIV (note that aids develops from HIV, you cannot catch aids), now I wouldn't stress out too much because Chlamydia is far more common than HIV in the developed world, and one off risks like this usual don't end in HIV infection, however it is possible and you need to test at 12 weeks for a conclusive result, you need to get a HIV anti-body test (blood test or oral swab) you can also test at 4 weeks, 6weeks and 8 weeks as these tests will give you a good indication (but not a conclusive result)