Thank you for all the information,
Antibiotic taken before test may cause false negative tests.
But it would not cause negative results on every occasion.
It is likely that you are not having UTI or STD if repeated tests are negative.
There can be other causes besides an infection.
There can be urethral syndrome.
You can read about this in this link.
You can take an evaluation by urologist.
I hope this information helps.
If there’s anything else I can do, please let me know.
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