I was sick from Nov of ‘19 till September of 2021. Depressed/fatigued/lethargic. I took one dose of Ivermectin when I was feeling sicker than usual (headache, etc). I kid you not, within 15 minutes my headache was gone and I felt like I was on speed. Like I felt normal again. I think anything that can be causing gut issues can be fixed with ivermectin, parasites would be the most lethal thing in there so clear those out and your body can probably more easily replenish your healthy gut flora.

Pro tip, look into your ethnicity and the foods eaten in your culture, especially the fermented ones with probiotics. Most of the unhealthy gut stuff comes from straying away from probiotic foods native to ones race, finding and consuming those on a daily basis will help with the rebuilding of healthy gut :D