7 year old daughter has blood in her urine is this an infection?

I took my 8 year old to the doctor because she said her vaginal area itched really bad. I thought yeast infection. So they ran a few tests, said she had blood in her urine, sent that off for more testing, for urinary and or kidney infection. They both came back negative. They gave her some cream for the itching and called it vaginitis. Now, a few weeks later, my daughter is telling me that she feels like she has to pee, but when she tries to go nothing comes out. Any ideas. I will be calling the doctor tomorrow.