Confused About Subtypes/Strains

I spent five months in a monogamous relationship with a Dutch guy in Amsterdam, his HIV status unknown.  Our sex was unprotected.  A month after we broke up (last possible exposure), I was tested at a clinic in Amsterdam, result negative.  The nurse at the clinic told me it was smart to return at/after the three month window period for follow-up testing.  Well, I moved back to the States after that and did my follow-up test at three months in my home town and still had a negative result.  My question is...  Do the rapid HIV tests in the U.S. test for the same strain/s that I may have contracted in Europe, specifically Amsterdam?  Also, without knowing my specific situation/circumstances, the nurse here in the U.S. told me that results are only conclusive after six months, which obviously made me anxious all over again.  I want to move on from this - I am worried sick while waiting out this "window period."