I gave up smoking a year ago, substituted cigs for mint imperials, and then hurt my back and was given naproxen which messed up my stomach. I continued to have "stomach issues" and went to one Dr several times. In December she told me "I don't have a pill which will cure everything" and I went home and cried. In January my OH said we couldn't go on like this and dragged me to see another Dr who listened to what I said, ordered the usual round of blood tests and in February I was told I was diabetic. She said that wasn't what she was expecting. I didn't have any of the usual symptoms, the only thing, looking back, is that I was always tired and often fell asleep in the afternoon, but I put this down to not sleeping well at night (which I still don't).
Incidentally my "stomach issues" and indigestion had all but disappeared after a few weeks of low carbing, then I got to see the DN who put me on metformin and they have gradually got worse again.