I'm fortunate in that I have ever suffered any side-effects from metformin.
My current doctor took me off it for twelve months around four years or so back. My blood sugar levels rose ever so slightly over the next two blood test he took (six months apart), so he put me back on it as a precaution. Every time he takes blood he says my sugar level is perfect, and that if he didn't know I was diabetic, he wouldn't know looking at the results. I'm thinking that if he says the same thing after the next test, I may suggest to him that I try going drug free again...
I should have had bloods taken back in January. The doctor put those off at the time, due to concerns over possible Covid-19 infection risks. He told me on the telephone that, as I have been managing the diabetes so well, he had no concern about delaying the tests in my case. We are hoping to see an easing of restrictions after Easter, so I may give him a ring and see if we can get those tests done.