Sounds like you've tried just about everything, but when I first read your post, the first thing that came to mind was, "man, she's so stressed out".. & stress is so hard to diagnose, its that mental "busyness" thats hard for a Dr to tap into & say, "You're overthinking & "trying too hard", calm down".. If you aren't sleeping well, nothing is going to work.. I know it seems almost impossible, but visiting all the doctors, waiting for the "results", constantly scanning the web & reading & reading & googling & thinking & wondering & reading & thinking & considering & thinking & googling & reading is GOING to inflame whatever is already irritated in your body.. You already tested negative for the heavy stuff by your doctors & blood tests.. You may simply be suffering from chronic stress.. If your mind isn't relaxing & you're not sleeping well then NOTHING is going to work..
I'm wondering what the cleanest way is for you to start getting some sleep (without use of anti-biotic).. You have the kids & are naturally exposed to a stressful environment, but we gotta find some time for you to nap, & ensure you're sleeping well.. Those kids need a healthy Mom, even if it means Mom needs some "Mommy Time" in a quiet room, with Enya playing, glass of wine & 2 hours to nap..

Hey, simply being a young parent & engaging the daily grind is enough to drive anyones digestive system out of wack..
Sounds like you need a vacation, maybe a stay-cation.. Babysitter, no computer access, maybe some fasting (relax the digestive system) & simply sleep, watch some movies, make some love to your hubby

sleep more, get a massage,.. just calm the entire body down.. Just gotta find a way to pump the brakes on these stress levels & relax.. I'm a thinker as well & have to save myself often from causing the problems.. Stress in some form or fashion is the root of all inflammation & disease.. If we can limit it, we've won half the battle