Well that is not normal at all. This could indicate damage to the kidneys or anywhere along the urinary tract including the ureters and bladder, even the urethra. Blood could be from inflammation, infection, tumors. Tissue is more serious. You need to contact your doctor and give a urine sample for urinalysis with reflex to urine culture to do basic analysis and also check for infection if indicated and probably basic CBC complete blood count and BMP basic metabolic panel or CMP comprehensive metabolic panelas a start. You should also consider seeing a urologist for further evaluation which will likely involve imaging such as CT scan and/or ultrasound, as well as possible more invasive testing such as a cystoscopy camera on a small tube that is inserted into the bladder.

Highly unlikely from flu. Bacterial infection likely. Lab tests needed. Urinalysis and culture. Rex