Negative tests always accurate?

Patient: I had a pap smear in June, which was fine. I had a baby in November, and then had another pap that showed signs of trich. I was then tested for trich and came up positive. I took the medication on Monday, and then was retested on Wednesday. This test came back negative. My partner was also treated, but we have not had sex yet. I still notice, however, a very slight smelly discharge and MILD itching that comes and goes. Can I have had a negative test, yet still have mild symptoms or is something elso going on? Do I need to be retreated?