Hi
@Aliea, from experience as a diabetic,, not as professional advice or opinion:
Looking up healthline.com, the only thing I can find which might fit with your symptoms and be related to use of increased dosage of metformin is
low blood sugar.
If you have a glucose meter a reading of below 4 mmol/ (or more strictly speaking 3.6 mmol/l) would be classified as hypoglycaemia (hypo = low, gly - glucose , -aemia = in the blood). If you look up hypoglycaemia in the search box right hand top corner you will find suggestions for treating it.
I would suggest you seek advice from your prescriber or a weekend locum service about your symptoms as soon as possible and also in case the cause of your symptoms is not related to metformin. Best wishes.