You need to see a urologist for possible IC and if you are clear there go see an endocrinologist to check for diabetes insipidus which relates to your pituitary gland, or your kidneys. You can look up the symptoms both can cause frequent urination. I have been having the same symptoms and was also cleared for the blood sugar/diabetes. Let me know what you find out.

Hey i get this same symptom from time to time. Don't think of it as an internal issue in which a system in your body is out of whack. The truth is if you are drinking a lot of water and constantly urinating it out within 30 minutes to an hour after drinking, it means that you are almost completely depleted of electrolytes and you are simply not making good use of or retaining the water efficiently. The body's main electrolyte is sodium/salt and this is released every time you urinate so i would recommend taking in plenty of sodium throughout the day while drinking water. Your lack of appetite is making your symptoms worse because you probably aren't taking in much sodium from various foods. It is very easy to drink lots of water without taking in sodium and urinating several times and in effect depleting your body of what sodium it has left. Don't be surprised if a lot of mainstream doctors don't have an answer. They rarely do because they are so focused on WHATS WRONG WITH YOUR BODY and HOW TO FIX* YOUR ILLNESS rather than what does the body need to function properly and heal itself. Our body's have amazing ability to heal but only when we give it the proper tools. Most doctor's don't know a thing about healing and only know how to give you a prescription drug that doesn't REALLY work. Most health problems are very simply solved. But they try to make it seem like a complete mystery. The two biggest causes of health problems today are 1. dehydration 2. mycotoxins in the grains we eat eg. corn, wheat,. I would highly advise to stay away from corn- it is the most infected of all grains by mycotoxins and can be devastating on the body in general but especially on its ability to heal-immune system.

Are you on any medications? Tons of medications cause dry mouth and throat, leading you to drink more water, leading you to urinate more. Some medications, such as allergy medications can cause headaches and even back pain. I had to stop taking Allegra because it was giving me lower back pain. Read the information about the side-effects of any medications you take, even over-the-counter stuff (look online for the side-effects of those, not just on the bottle).

I agree that you should also make sure you are getting enough electrolytes with your water. Sodium, potassium, calcium, etc. If you urinate an hour after you drink water, this doesn't mean you are urinating out the same water. Your body is trying to keep things balanced. Is the urine usually really clear or light yellow, or is it dark yellow?

If it's defiantly not any medication you take, I think it would be prudent to have your kidneys checked. I agree that a urologist would be a good next step. Have they done a urine test?

Calcium deficiency doesn't really cause the symptoms you are describing. It causes muscle spasms, cramping, twitching, and slight numbness (usually starting in the lips). Plus, both blood tests (although different) showed results in the normal-range. If you had something that caused a calcium imbalance, you wouldn't be normal just for the tests.

I hope you can get a diagnosis soon. Good luck. Let us know if you have any more questions. Also let us know what the doctor says. It may help someone else on here in the future.