Do STDs Cause Persistent Burning Sensations During Urination As Symptoms?

Question: In XXXXXXX for the first time in my entire life I contracted an STD when I was exposed to Chlamydia. My main symptom was significantly bad burning during urination. Instantly I was treated and the burning went away. TWO WEEKS later I went back for a re-check and results were negative. At the time i didn't know that you are supposed to wait at least four weeks for a re-check.

Since then however, I have not had a single symptom. However, the issue lies with my new girlfriend of 2 months that I am sexually active with. (She is using birth control) Recently she started her period but it is now lasting far longer than normal, going close to two weeks. Paranoia has set in that I was never fully cured from the Chlamydia and have maybe passed it onto her. **It should be noted though, that three weeks ago before she began regular birth control she took Plan B which also could be causing a simple prolonged period on her part. She personally thinks it might be a "cyst". She is going to the doctor on Saturday.

One of my main questions is... I know this STD is often a "silent" one with no symptoms, but if I had a strong burning symptom at first, wouldn't that have continued or been there for me at some point in these last 6 months if my treatment didn't work?? Do you really think I still have this and have now passed it onto her?

Basic antibiotics prescribed by doctor.
Two doses. I am told that I should have waited at least four weeks for a re-check but instead waited only two. Still, no symptoms since. But chlamydia can also show no symptoms as we know