As you probably know, metformin has zero impact on whatever carbohydrate you eat. What it does is to increase insulin action and slow down your liver making glucose itself. This usually means a relatively small variation in blood glucose levels.
The level of change you're reporting is quite different, and as said above, the levels are high and need to be looked at. We can't diagnose on here but if I was getting those sorts of results, particularly if I couldn't explain them, I'd be looking for urgent medical advice.