Colonoscopy help

I just went to my long awaited gastroenterologist appointment and I’m depressed about the results. He said I’m too young to have a problem and didn’t help me. He’s giving me a colonoscopy yet I don’t even think I can get the poop out of me to get the colonoscopy. I’m going to try to get the poop out of me. Does anyone have any tips on how to get very constipated poop out quickly? The appointment is in 2 weeks. I poop about once a week and very little when I poop.