UTI and pregnancy?

So for the past few days I've had some moderate cramping, back pain, and the urge to urinate constantly. I thought it was possibly a UTI or kidney infection since I am prone to them. I went to the dr and all tests came negative so no uti. AF is due tomorrow and I'm curious did anyone have symptoms similar to a uti that turned out to be pregnancy symptoms? The cramping does feel like my average period cramps. More like a sharp pain in my ovaries.