Hi and welcome tot he forum! I am glad that I can help you.
You want to know the cause of the symptoms that you experience.
Blood in the urine may appear in one of the following medical conditions: urinary tract infection (such as cystitis), kidney stones (when they pass through the uteters or urethra) and cancer of the urinary bladder. In cases of cystitis individuals experience additional symptoms such as pain in the lower abdomen, frequent need to urinate, pain or discomfort when urinating and itching in the genital area. In cases of kidney stones, individuals experience pain located in the lower back which irradiates towards the front and down towards the genital area. In cases of cancer of the urinary bladder, individuals don't experience any additional symptom (painless bleeding in the urine).
Given the data that you described, you may or may not experience any of the medical conditions listed above. You may need to have a laboratory test and bacteriological culture from a urine sample to rule out or confirm possible urinary tract infection. You may also need to have a native RTG scan of the abdomen or ultrasound to rule out or confirm possible kedney stones. A cystoscopy to rule out possible cancer of the urinary bladder may be needed as well.
Please keep in mind that I provide medical information only. I am not able to diagnose medical conditions online. Please contact your doctor for further advice and information about diagnosis and treatment options.