UTI false positive pregnancy test

I took a test this morning and it came out to be positive. We used the clearblue digital. But we went to the doctors to double check and the urine test came out to be negative.The doctor said I have uti and when I test with the first pee is when hormones are at its strongest so that's why it was positive. But my breast still hurts and I have abdomin pain. I just got off my period on the 15th. What could be going on? What's the chances of pregnancy? And can the UTI affect the test?