I don’t know about single dose treatments. I had this about 14 years ago. Protocols may be different now.
Anyone given a prescription to be taken over a period of days should be sure to take all the pills as directed, even if the symptoms subside earlier. Some tend to take antibiotics only as long as they experience symptoms, then stop short. That is bad practice and is what contributes to drug resistant strains.
I took erythromycin for 7 or 10 days (don’t remember exactly, but it was at least a week). The odd feeling continued for a few weeks after that. I had a bad case according to the doc. My girlfriend at the time tested positive for chlamydia. We had been fucking for months, so I assumed that’s what I had. She didn’t have any symptoms and only got tested after mine became apparent.
It was nasty. Itchy urethra, somewhat painful, with a lot of whitish pussy discharge. Not fun. That episode taught me a lesson about safe(r) sex. What if the disease had been something worse like hepatitis or HIV? Makes you think. Or at least it should.