Urine test contains blood. On this.

My daughter is 3 years old. She has recently started nursery in UK. She has been sick every week . Here Gp told that children will be sick once they start nursery. Last week Friday she got fever and we went to go and took urine test they told urine test contains blood and asked us to go hospital. Later they checked again they told it might be because of the infection she got. Once it cleared we will check and then we will proceed on further. Later on Wednesday she again got high fever like above 100 C. Again we went to hospaital here, there doctor told she got tonsillitis and gave penicillin antibiotic. He told she contains light blood in urine test. It's not worried thing. They asked us to wait for further 2 weeks once the infection got cleared. She is passing urine normally no pain in that area. But we are really worried and stressed out of this. Kindly suggest advice on this.