Why do I keep showing I have moderate amounts of blood and trace leukocytes in my urine?

I had a urinalysis done a week ago, and it showed i had large amounts of blood and trace amounts of leukocytes in my urine. The urine was sent off for culture, and it showed no growth, and they asked me to come back and give another speciman and they would retest the urine. It came back positive for moderate amounts of blood, and trace amounts of leukocytes as well. I just dont understand what is going on with my body lol.