Honestly at your age, we usually don't think of sinister pathologies like a cancer. Your symptoms have considerably improved after taking antifungals, which is a direct clue that the symptoms you have are from an infection.
But having said that, as per standard guidelines, any unresolved or persistent hematuria (blood in the urine) once the infection has been treated, should be evaluated in detail, to rule out any thing serious like a cancer. However there are many benign causes for this, which are much more common than a serious disease like a cancer. These include a residual infection, stones, or kidney diseases.
I can understand that anxiety you are having, but please note that Cystoscopy is the best test to help find a solution to your problem; and irrespective of the underlying condition, the earlier (and properly) it is diagnosed --- better is the prognosis.
Stay relaxed and proceed with the evaluation as rightly suggested by your doctor.
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