I had very bad side effects with Metformin and a statin, so stopped taking them over a year ago now.
My BG is entirely normal - achieved after stopping the tablets, my weight is reduced my energy up, and I can't see any reason to go back to taking them.
Although it is regarded as a good medicine, non of the effects I reported were recorded - so I do wonder just how many adverse reactions go unrecorded and unreported nationwide or even worldwide. I was taking just one 250 whatsit sized tablet of the Metformin - I did manage to take two on two days, not consecutively, but that was just hellish.
I think that you need to argue your case with your doctor, because we are told how safe it is to take Metformin, but for me taking something which made life not worth living is no way to try to survive.