Oh yes, I know what you mean!
It took me 5 - 6 weeks to build up to 2 Metformin twice a day, but over the last three weeks I have had to cut the Metformin as the side effects have been very dramatic!
No pain at all, else I'd think it was a bug!
Interesting that some people say they also feel sick.
Again, over the last three weeks I find that I feel nauseous quite a lot of the time, nothing I eat tastes good and I could easily go without food much of the time .... obviously as a very good and well-behaved diabetic I don't miss meals .....
So, the nurse said to wait till after my first 3 month check in January then see if I need to go onto slow release.
I quite hope I do!
Despite this, I'm not really losing any weight, which is rather disappointing!
Hope things sort our for you.