Re metformin, I actually found one particular brand made me feel really bad, and I swapped to the slow release version which I'm fine with. With my original brand I was OK, but I found on a few occasions when I ate slightly more carbs, it gave me the runs; this result was confirmed
here - see under the section Gastric Distress. So both a slight modification of diet, and changing to a different brand (or slow release version) of metformin might help?
Robbity