@zand I'm so sorry you are going through such a hard time. What you describe is one of the two scenarios I fear from Covid. Not enough attention is paid to this. I hear people so often talking about the risks of death from Covid, but rarely about the threat to quality of life for survivors, even though I have read that 10% of people infected will end up suffering from "long Covid". You are certainly not alone. I did a quick Google
BBC 4 long covid and found a lot of listening! I gather that at first, as with ME in the past, a lot of people were told it was all in their minds, but that stage is past.
Please don't give up hope. You have been coping with diabetes, (not everyone does) now you will (slowly) overcome Covid. I prescribe small frequent treats (not doughnuts!), listening to your body, resting, mild exercise, healthy and delicious food, safe social contact (eg here on the Forum). I don't know if your circumstances will allow you all of these, but as many and as often as possible. Very best wishes. Keep us posted.