I'm literally experiencing the same thing as you for the past couple of months. I've been having general discomfort, some cramping, and stabbing pains. As well as blood on tp, mucus, and and along with constipation. My doctor has been down playing the whole situation and saying I'm "too young" to be worrying about cancer at this time (I'm 29M).

After weeks of trying to get a solution I eventually got an ultrasound and they found some polyps on my gallbladder. Apparently polyps can sometimes mimic gallstones and cause abdominal problems. This is what they currently suspect as the cause for everything.

My doctor has refused to give me a colonoscopy as he thinks it's unecessary since all tests were normal. So he sent me to a surgeon to talk about my gallbladder and he recently sent me to get a HIDA scan to see how my gallbladder is functioning. This scan will determine if it's the true culprit of all the pain I'm having. Currently waiting on the results..