Blood in Urine and oliguria that comes and goes

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So i got tested had blood in urine and i have oliguria that comes and goes i got my blood tests all normal, no infiection in urine no kidney stones found on ultra sound just constant micro blood and decreased urination that comes on for a week then i can urinate quite a lot for a few days and now the oliguria is back i got referred to a specialist do any of you know what it could be im concerned and i have to wait ages for my appointment