Hello and welcome to MedHelp Forums. I'm very sorry to read you are having a difficult time. Your first thing to do is to again, speak to your doctor. You have had a coloscopy that is recent and your findings at that time were not such to raise the suspicions of colon cancer then or now with your doctor. Colon cancer is slow growing and that is why screenings are important because it allows it to be caught in treatable stages. The family history you have has already been taken into consideration. I would think a question for the doctor would be if the insurance company was not an issue, would they think you needed a colonoscopy right now?
There is an alternative to the coloscopy called Cologuard Here is some information on it https://www.webmd.com/colorectal-cancer/home-test-colon-cancer-cologuard#1 It's an at home test that is easy to do and non invasive. It provides fairly accurate results, however, if you test positive, you will then require the full colonoscopy. It's less expensive than the colonoscopy and, thus, insurance companies do like it. So, that may be an option to discuss with your doctor.
Since you've had IBS as a diagnosis and constipation, this could be more of that. Hydration is really important. Here is some other info on conquering constipation. https://www.webmd.com/digestive-disorders/for-women#1