I posted a link in the other thread of my experience w/coffee.
I have a love/hate relationship with it.
Are you taking any sort of probiotics on a regular basis? If I am regularly(like, every day) drinking my homemade kefir, I do better. But, the kids have been "helping" me drink it, so there's not that much to go around (not to mention the amount of milk we'd go through to make a lot of it....$$$)....
*For me*, I had a similar response to green tea, though with my gut health getting better, I can tolerate it better now.
FWIW, my go-to for the last couple years has been black tea with a bit of honey and a splash of milk or half and half. YMMV
And I indulge in coffee every once in a while...though my last experience was not a happy experience.
Maybe try Matcha? or Yerba Mate'?