Well I am not pre diabetic yet, but it runs in the family so only time will tell. but I do have an under active thyroid, so like you have been told to lose the weight and exercise more, stay of the sugars and eat porridge for breakfast. Porridge is fine for the first few days and Liz suggested with cinnamon which is actually very nice. I like it with raisins to.
My mum who is diabetic suggested I have my none sugar cereal but just half the bowel and a piece of fruit either with it or after it, this is what I do now when not eating porridge. I think for our health we have to do as we are told, but for our sanity a little sin rarely, shouldn't do us much harm if we are willing to suffer the consequences. Me I am not, I take my thyroid tablet every day, I don't eat the sweet stuff because I just feel ill if I do.
have I missed my ice cream my all time favourite, well yes, I had a small one the other day and was very ill after wards, so I won't be having it again.
It will be interesting to see if your nurse becomes ill with diabetes or thyroid problems, both can start because of over weight. a good herbal to break down fat is Lecithin. I always forget to take mine.

I have to be -*test*-('")ed again in 6 months to, to check for diabetes and see how my thyroid is doing.
Liz just do what you can and as has been said just take one day at a time, don't beat yourself up about it.