I'm not sure how being a diabetic would disclude you, but I am not doctor. A few of my good friends have had lasik, most with very good experiences. Typically people with lighter eyes have more sensitive eyes though and my one friend with blue eyes had said it hurt a ton, after the surgery was over for about 45 minutes. But after that he said it wasn't so bad and he is able to see perfectly. (He also had said that he left the doctors and he didn't have a hat on, only the dark sunglasses and therefore some sun got in and hit his eyes which caused the pain)
Two of my other friends had lasik and they were fine, and they are now able to see perfectly and love the fact that they had Lasik.
From a scared point of view, I totally see why you would be scared, I would be too, but I don't see why not just go for it, make sure you have a reputable doctor, and I think you will be fine.
Just be careful right after the surgery and stay away from bright lights and keep your eyes safe.