Do you know how Metformin works? It does not directly lower BG.
Members on a forum can not advise what you should do about medication dose, but I have before referred you the clinical experience of diabetes experts. Dr. Westman in this talk https://www.dietdoctor.com/lchf-dia...dr-eric-westman starting around minute 21, gives seven patient examples of the weekly range of Glucose Minimums and Maximums, when he decreases and/or removes meds. The range of Maximums was 130-200! The range of minimums as low as a 72, but the median closer to 100-110, one up to 140.
Dr Fung posted a "what to expect with blood sugars" on his old site, and he lowers medications when BG are in the 5-7 range (7 mml. = 126 mg.)
Considering you started at 325 pp...an average of 122 should not unduly alarm your GP. Keep records of each reading and discuss it with your doctor at the regular appointment. You are doing great with both quitting smoking and carbs