Is my gut biome changing?

Add some soluble fiber perhaps? This is a quality product, imo.

https://www.amazon.com/Heathers-Tum...l/dp/B0002ON8DU

Or some low carb fermented foods to restore good bacteria:

https://www.culturesforhealth.com/l...ermented-foods/

I make kefir, and always second ferment it to further reduce lactose.