Frequent urination, excessive thirst, increased appetite but losing weight, headaches w nausea, and chronic fatigue. Possible causes?

Diabetes mellitus? If a patient is having frequent urination, excessive thirst, weight loss and fatigue, the most common illness that causes this is uncontrolled diabetes mellitus. Checking the urine for glucose will make the diagnosis. Ask pharmacist for test tape or strips to check urine for glucose. If it's diabetes, the test will show large amount of glucose in urine. If so, need to see a physician urgently.