I too suffered badly with Metformin. At first I told the doctor I felt like a smelly old volcano. She said persevere but it never really got very good. I was on two doses and she wanted me to work up to three but it upset me too much so stuck with two but have been very careful with carbs.
Then a few months back I found it getting really bad again and in the end had to seek advice. I had pains all over the place, was convinced I was anaemic and had to stop taking them and the doctor ordered blood tests . My new doctor, who showed more encouragement and interest than any of the others asked me to leave it off for two weeks then gradually re introduce it. He said if that didn't work we would have another chat about a different med, probably SR. He checked my blood results on the computer and told me that I appeared to have had possibly some form of food poisoning that might have been making me feel so dreadful. might have had it for some time. But at least a good pummelling had re assured me that I didn't have any blockages. A good pummelling, because I am a fairly big lady, but shrinking very gradually. Also told me that my blood was 100% so I was not anaemic.
I did as he asked, convinced that I would be going back for the SR and incredibly have tolerated it much better, even got up to three a day. No longer leaving the house with the 'emergency# . bag or worrying about the state of any toilet have used, always had the wet wipes handy
I take some supplements and check my levels most days. My morning reading varies between 6.5 and 9 and my long term reading after bold test was 6.2.
76 years old and diagnosed type 2 about three years ago