Drastic increase in Insulin needs????

Why, over the course of a month, would my insulin needs have dramatically increased?

For the last 3 years + I have been able to live on about 20-25 units of Novorapid per day, covering both my basal and bolus needs. Now, all of a sudden, I’m up to 35-40 units per day. My ratios used to be about 1 unit for 20/25 carbs. Now I’m at 1 unit for about 5 to 10 carbs. For me that is an unusually high volume. It’s scary because in the past, taking 6 units of insulin for a meal would most certainly mean having a low. I was nervous at anything over 4 units and would dual wave anything higher. Now, 6 units is seemingly nothing. Even 8-10 units per meal, without and dual or square waving, is fine. But I don’t get what would have happened in my body over such a short period of time.