Hurt my gut system very badly 12 months ago from Antibiotics I took for Lyme. These were wide spectrum Antibiotics for several months, mind you.
My gut was ravaged; I scoured every Internet site for how to heal my gut and tried all the food Elimination Diets I read about.
In all honesty to you, the reader. When I finally gave up trying so hard to heal it, it healed. It took about a year. I do have some food sensitivities , but the foggy headedness, thrush in mouth, etc is down 95%.
My advice should you choose to follow it, is to stop eating sugary snacks, salty snacks, and anything else you know isn't good for you. Processed wheat/gluten products are typically inflammatory as well, especially with a damaged tummy. Stay away from any pasteurized dairy as it isn't healthy for you anyway (raw milk is ok if you don't have dairy allergies). But watch reactions to what you put in your body. You'll know if it's not good for you.
I was the biggest doubter; I had no faith it would heal; but looking back, the biggest factors were:
1) NOT eating things that are processed or sugar/salt laden.
2) Letting time pass and inevitably heal it on nature's own timeline (not mine).
3) Being consistent with doing my best.
Over time, you'll refine your diet to what works and it will heal over time. In western society we are so set on instant gratification that we are at times humbled into slowing down and trusting/waiting.
Do your best, over the long haul, and it will heal.