Negative Result For STD Test. History Of Chlamydia Infection Positive Result For Guy Who Had Intercourse. No Painful Urination, Little White Discharge. Ideas?

I went in for my routine check up and had sex once while waiting for my results. I came out clean but days later the guy I slept with tested positive for chlamydia and, as a precaution, I asked my doctor to prescribe me one 1g of Zithromax. This was last Friday and she told me to come back in 5 weeks. The strange thing is she did an STD paneling on me and I came back clean for chlamydia and the guy and I slept about 6 to 8 times in between that time period and my result was clean after 3 weeks of no contact. Is it possible that my immune system could have preventing infection considering that I work at a health food store and take many supplements. Also, my other question is if I had chlamydia should my discharge be a certain color? It is only white and the amount is decreasing each day? Is there something i should look for? I have no painful urination, no irritations, just the white discharge.