Thanks for your query
Hematuria ( blood in urine) may be due to many reasons. In your age group it may be due to infections, sexually transmitted disease
, renal or urinary bladder calculus
,tumour,familial,idiopathic any many other rare reasons.
Proper history should be taken first like history of pain,fever, weight loss
, burning micturition, any discharge etc.Ultrasound
of abdomen can exclude many conditions .so you first you go for ultrasound of abdomen along with routine blood investigations.
Don't worry at all. Get well soon.