there is a form of diabetes called diabetes insipidus which is marked by significant dehydration and the requirement for constant intake of fluids and pale diluted urine. It's pretty rare and difficult to diagnose. Unlike Diabetes Types 1 and 2 this has no impact on the eyes. This is a condition that can be caused by lithium. Get your blood tested. The condition often occurs with that of very high calcium and low thyroid/parathyroid hormone numbers. Unfortunately there is not much that can be done other than to keep oneself hydrated.