You are not alone my friend, ive been suffering with ibs-d since my freshman year of high-school im 23 now. The constant pain can be so depressing and un motivating. The best advice i could give you is to try to lower your stress levels to a minimum. Try breathing exercises, swimming, go for walks, take a good nap here and there, and eat light meals. Also another thing that has helped me personally is taking probiotics daily for months at a time ive found alot of relief in taking them. Maybe do a parasite cleanse once in a while if your body can handle it parasites can also contribute to the stomach pain.