I thoroughly agree with the above 2 posters, it sure sounds like a blood sugar problem to me. Hopefully, they will do a 3 or 5 hour glucose tolerance test, an insulin resistance test, and an A1c test. These should pretty much tell you what is going on.
Carbohydrate cravings, blurry vision and excessive thirst thirst are hallmarks of a glucose utilization syndrome, as pointed out by remar.
There are several tests indicated. A fasting glucose or insulin clamp protocol, as well as an hba1c.
Provisional diagnosis: Rule out diabetes.
See your Dr. It sounds like you may be having trouble with your blood sugar. When you have your appointment set up don't eat anything and only have water for at least 8 to 12 hours so they can do a fasting blood sugar test on you. It can be done right in the Drs office and only takes a minute to do.