I have tested positive for a coronavirus and diabetic, just tested my sugar level is 31.1 mmol/l?

Seek medical care: That is a very high blood sugar. How to manage that depends on a lot of other factors. If you do not already have clear instructions as to how to manage that from your doctor, then you need to talk to a doctor urgently. If that is not possible, then someone should take you to get care at a medical facility.

High blood sugar: 560 .3 mg/dl (31.1 mmol/l) is very elevated. It you have never had these types of elevations in the past, would seek emergent assistance. Do you already have a plan worked out with your doctor about what to do with these types of elevations?