I was struggling with digestive issues from about 2019 after a severe work burnout (I think triggered by sleeping with a belly full of casein powder and also don't eat gas station sushi) but finally got to the bottom of them only this year. The solution was holistic, but basically my body's inflammation was so high from stress that my gut couldn't handle a piece of bread or a cup of milk, much less beans or nightshades.
Specifically I have sleeps apnea, my cortisol was 1.5 times the max upper range, my thyroid wasn't getting signals from my brain, I had adrenal fatigue, my B12 levels were low (the liver stores 3 years worth of B12, that's why vegetarians often crash the third year), my D3 was low, my BMI was way too high so aromatase was turning my T to estrogen, basically my levels were all off. My nurse gave me some prescriptions and a supplement cocktail and I found relief within just a few days. My joint pain went away, my patchy hair filled in after a couple of months, no more brain fog, etc. If IBS is a spectrum, then my experience has been that it is curable even if it's been going on for 5 years or more, although Crohn's disease probably has immune system markers that require specific treatments.
Now my digestive issues are in remission and I can eat everything I did before (edit: including gluten), although spicy food maybe overstimulates my peristalsis. So that's just the onset of oldtimers disease I guess.
For some level of immediate relief, try eating mainly big looseleaf salads for a few days, drink kefir, and drink a scoop of organic turmeric powder to calm the inflammation, all daily. I also found 2-4 psyllium husk capsules and a large glass of water daily to be highly beneficial, but watch for flares since there are different types of IBS. And stop all multitasking (edit: choose the path of least anxiety), add slack to your schedule, make 20 minutes per day to meditate, and stop believing that you are stuck and this will last forever. I believe that night terrors and bodily symptoms are our subconscious trying to get our attention so that we do the healing work to address the pain of our isolation and suffering.