Do i have UTI or cancer or a kidney infection?

this morning i woke up and had pain in both sides of my lower back, this week when i urinated it would come out really yellow ( probably cause my class schedual doesnt give me a lot of free time for the restroom) but still, and when i deficated in the toliet there was blood on my feces. im 18 my hunger definetly is't diminished and im not always thirsty, and i have been urinating today almost every hour or hour and a half