Why do you want to kill yourself? Your partner showed you her test results which (it appears from your posting) indicates she is negative for all those STD's. Why would the clinic lie about the test results?
You got a fungal infection from taking antibiotics. That's not unusual and has nothing to do with any STD.
It's important to understand what the test for Chlamydia involves.
Unlike testing for viral based STD's (such as HIV, for example) which checks for antibodies the immune system begins to produce after transmission, testing for bacterial based STD's like Chlamydia and Gonorrhea involves checking for the actual bacteria connected to these diseases. This is typically done by swabbing the genital/anal area or through a urine check.
IF the swab misses picking up the bacteria (for example, it has traveled up into the fallopian tubes in a female) then, of course, the test results will come back as negative since no bacteria will be picked up.
A physician MIGHT still prescribe the appropriate antibiotic treatment as a preventive/precautionary measure based on symptoms the patient may be experiencing even if the test results come back as a negative.