Can you help what disease i am going through?

[ToGodAbove]

I poop a lot everyday. Sometimes 3 or 4 per day but my stool is not water like or oily. It is type 3 and 4 in bristol stool chart so it is normal. Recently i am taking ciprofloxacin and mefenamic acid because my Dr. said i have UTI 'cause of backpain lower abdomen and side pain and having diarrhea and even urinating yellowish a lot. When i start to take medicine i starting to feel that if i finish pooping and stand up i feel like i gonna poop again and i feel pressure in my rectum anus area. Sometimes there is pain i don't know where but it is in my abdomen area and there is pain in my lower left stomach if i touch it but when i don't touch it the pain will go. It build stress and I become anxious because that day i go to doctor is the day i will enrolling to school and everyday it keeps bugging me if it is colon cancer and I think I'm depressed right now. By the way I am 19 years old and my father and mother doesn't have cancer even my grandparents. This is the first time i feel this symptoms. Please can some tell me what it is?

Thank you~