When the kidneys become full of glucose they lose the ability to flush out the extra glucose and then the body begins to draw extra fluids out of the body. This is the first and most common sign of diabetes.
When you kidneys work overtime to clear the glucose you will often feel constantly thirsty. If you feel like no matter how much you drink you cannot quench your thirst it is a good idea to be tested.
You have probably heard that there is a strong link between diabetes and obesity, so weight loss as a symptom may seem counterintuitive. However, with Type 1 diabetes this is a warning sign. With type 1, the pancreas stops producing insulin, usually due to a viral attack on the insulin producing cells. The cells become starved for an energy source and will begin to use fat stores and lean muscle leading to unexplained weight loss.
You can feel very tired when cells are unable to get glucose from the blood. So this is another sign.
This symptom occurs over time. As blood glucose levels increase in the blood stream nervous system damage can occur. Since this is a gradual process, much damage can be done before a diagnosis is made. This leads to tingling and numbness especially in the extremities.
When sores do not heal properly this is another sign. Your blood circulation may be effected and the oxygen your body needs to take care of white cells may be effected.
In addition to all the other signs and symptoms there is also itchy skin and dry skin as well as blurred vision.