Severe constipation and rare disease

Hi! I hope you can help me (and warning it will be graphic). I have a rare genetic disorder and among other things it causes constipation. Over the past year my constipation keeps getting worse. I eat a high fiber diet and drink a lot of water but I usually only poop every few days with the use of a strong laxative like exlax and I have to strain a lot. Sometimes I pass out on the toilet from straining. Stool softeners do nothing. I feel really nauseous and am in a lot of pain, I feel like my colon is stuffed. Today I took exlax and also did a suppository and only pooped a few pebbles. I can feel as massive poop in my rectum but it’s rock hard and I can’t push it out. What can I do to poop?

I spoke with my doctor and they won’t provide further advice, they said I need to come in for an appointment, which is scheduled in 2 weeks. I have never had a colonoscopy or any tests with regards to my constipation.

Hi thank you. I have tried prune juice. It’s not working so far but I will keep drinking it.