Where to go from here-- Recent Hospitalization for Kidney infection, symptoms...

[SMD]

...back but negative urine culture!? I know there are always posts that are similar, but if anyone has been in this situation I'd appreciate some guidance. So, about 3ish weeks ago I went to the doc for normal UTI signs-- a reputable office. Docs office didn't seem to worried, and gave me a script for an antibiotic. Later that night, I ended up in the ER with an accute kidney infection. That doc put me on some stronger meds for 10 days. I was feeling much better, but it has been a little over a week after meds, and I am starting to feel the same issues creeping up with back pain and "flakey" urine. I went to the doc for a followup, and they said test was neg. I was skeptical, bought the strips to test at home, and they came back on the lighter end of positive-- the same day. I feel like I'm going nuts here because I don't know if I'm really looking too far into any ache and pain, whether to trust some machine, or some cheapo strips. So I guess my question is, I have heard birth control (I am on the Nuvaring and it was out for a few days the time I was in the hospital) and or an antibiotic of cipro cause a false negative? Like i said I have not taken it for about a week and a half. And why would a cheapo test tell me positive when a fancy machine says 0% down the line?