Suggest Treatment For UTI

I am a 20 year old female. I went to my doctor because I had been feeling very weak and lightheaded. She took blood and urine. She said I had a UTI because there were too many white blood cells in my urine and there was too much bacteria. She gave me antibiotics to take. I have no symptoms of a UTI at all. She said that sometimes the only symptom is weakness. Is this true?