Not sure what’s going on

So a few months ago I had a UTI, was taking prescribed medicine for it but had to get more because the symptoms came back when I was finished with the first round. I finished the second round and let my doctor know that I am once again, having symptoms. My urine smells like ammonia, is dark and cloudy, lower back pain and I smell like fish down there... she did a test and said my urine is clean. Then her assistant called and said all of the symptoms I’m having is because I’m not drinking enough water? I’m 21 weeks pregnant also. Anyone else experienced this during pregnancy?