I Have Severe Nausea, So Bad At Times I Can't

I have severe nausea, so bad at times I can't eat. I lost 40lbs in 10 month not even trying. A lot of times I don't have an appetite. I have ibs, had 2 colonoscopy's done and they cant find anything. I know I have divirticulitus because when I eat popcorn or some seeds I am in tremendous pain. Nothing show on the colonoscopy. I have intestinal pain. Weakness in my legs for 6 or 7 months now. I don't have health insurance & my doctor wanted me to have another colonoscopy after about 3 yrs and I told him I could not afford to pay for it. My mother died at 49 from colon cancer and her mom in her 60's and her mom in her 80's. Just want to know what is wrong with me without thousands of dollars of tests that they can never find anything wrong with me.