I Have Been Having Lower Stomach Pressure For About 2

I have been having lower stomach pressure for about 2 weeks. I saw my urologist who said my urine was fine. He sent me for a CT of my abdomen /pelvis which didn't show much of anything. I am getting worried because the pressure is not going away. I was already scheduled for a colonoscopy before all this began which is in a few weeks. Any ideas what else it can be? Thank you.