The last time you posted you were still having a carb-heavy diet, has that changed? Have you gone low carb drastically? Because that can cause carb- or keto-flu, which makes one fatigued for a while, headachy and such too... It's one of those things you have to get to the other side of after a week or two, but usually, having some additional electrolytes'll help. Supplements, bone broth, coconut nilk might perk you up if keto-flu is the case. If you haven't changed your diet and are still eating cereal bars and the like, do check your blood sugars and see whether they're still high and your diet needs adjusting. You're on a high dose of metformin now, but that doesn't do much of anything about what you're ingesting. It might make you a smidge more insulin sensitive, and it'll make your liver dump less glucose, but that's it.
The fatigue can be absolutely crushing, so I do hope it'll resolve soon, one way or another!
Jo