Can Kombucha make you feel like ur getting a stomach bug an hour after drinking it? (burning sour feeling in abdomen mixed with a mild stomach ache + nausea) I think this happened once before after I drank a bottle of it but I'm not sure.

Maybe. I'm not sure if I've hear this before but it is entirely possible if there is a timing correlation between when you drank it and the onset of your symptoms, that is likely the cause. Kombucha can be fairly acidic (pH of 2-3) because it contains by products of what is essentially fermentation. If you already have mild problems with acid reflux, kombucha could make it worse.