Welcome to HCM,
After going through your history,You must understand when period begins initially cycles may be anovulatory and may be irregular once you grow up they become ovulatory and regular with slight variation.
You have developed UTI which can cause mild Haematuria or blood may be coming from uterus
hence you need to see a Gynecologist and get abdomen Ultrasonography
and Urine R&M along with Culture and sensitivity.If there is any abnormality it can be treated.
Once urinary specific antibiotics are given your UTI will be clear and hopefully your period will become normal please do not worry.
Even if you get period every month do not worry it is normal.
Please also do not worry about future may be you focus at this age on your study,wish you healthy and happy life.