3 year old with Calcium Crystals in Urine.?

We have been battling with the blood in urine for about a month now and we were told to take her back to the er last tuesday per dr on call because she had a fever with the blood in urine. I didnt think it was related but anyways we get there and they think its a UTI which it wasnt (urine cultures confirmed it) and this time the blood was worse. So we went to the nephrologist again today and I took a sample of the bloody urine since she dosent do it all the time. And she looks at it and said there was def blood (which you could see) and she said there were calcium crystals. The last visit she had blood we could only see with a microscope and some crystals so they sent it off for a calcium level check and it came back elevated. Well this time she seen quite a few of them and then she also had to pee for them today which contained no blood at all but contained crystals but they could not tell what kind they were. So they are sending it for another calcium check that we will know tom what it is.They are also referring her to urologist as well. Should I be concerned with the calcium crystals being in her urine now? Moms day out said she complained of her belly hurting a few times today and she will also leak on her self. Should I be worried? I heard the build up of the crystals could cause kidney stones. We have changed her diet and they are holding off on putting her on medicine because she is only 3.