You really are in a hard place right now, so feeling for you. I had similar problems that you have but not to such a degree, and so have a wee inkling of what you are going through, including the marriage break up in the early 40s scenario. and the baby loss.
Have you tried a gluten and dairy free diet, intolerance doesnt show up on tests, its on history only. And until I went strictly that way, I finally got a life,
I'd be wary of having the prolapse fixed, until you have your diet under control which is controlling your constipation, No surgical suture and re-design can stop it happening again.
Your migraines, your brain fog, your dark grey cloud and anxiety, all lead to the 'opinion' that you are somehow poisoning yourself and gluten sure is something that can do that. Esp the beer and starchy foods is tho you have a candida problem which also can come from chronic gluten irritation of the gut wall.
So what is my opinion,???
its worth the 3mths of strict diet, that is checking EVERY label, cut out the processed foods, try and go to cooking from scratch and getting fruit and veges in. They dont have to be fresh, frozen is fine. Then if you see improvement make that your life
Be prepared for other things taking over the irritation as the gut starts to repair. It took me years to work out that SOY causes gastric bleeds,
Just as a hint, I milk my own goat, for milk, I have rice as my go-to for crackers and bread replacement, [got to put the beetroot on something]! I try to get most food from my orchard and garden, which I fully understand is hard to do if you dont have acreage.
Meanwhile for your poor fog brain, write notes, lots of magnets on the fridge, retrain yourself to think, use your notes on your cell phone. do puzzles and other memory games and try to go out for a walk daily.
Re train your gut with exercise, food and fluid, and you may 1. not need the surgery if its manageable. 2. feel better. 3 start living
I was 42 when my new life started and tho it crashed again at 50 for other reasons, Im more alive now 20yrs later than I was back in the mid 30s suffering many problems