The low carb diet according to your graph is If not faulty, not causing spikes and maintaining levels even though you are still in diabetic levels. The glicizide should be working unless the glic is not what is required to control and you .might need another type of diabetic med.
You are aware, that glicizide can cause over time, low readings that can give you hypo symptoms. Do be aware of this as your overall blood glucose levels do come down.
Dosage with low carb is important with glicizide. And it should come as no surprise that it is a temporary measure. So if you get no improvement, to back to your gp, to have a review of taking glicizide.
Keep safe.