Did they run HgA1c tests on you in checking for diabetes? With your thirst and sweet smelling urine, along with a family history of diabetes, it would be worth investing in a home blood sugar check machine- I've read they can start as low as ten bucks & obtaining some at home some fasting blood sugar levels. Are you using sugarless gum or sugarless hard candy for your dry mouth?
Dark urine when you are drinking that much could be a sign of something wrong with the liver- did they check your liver function?
Very dry mouth and thirsty my urine is sweet to smell an dark in colour and I've had blood test an they Said it was normal but I think they haven't checked all forms of diabieties.
Diabetes runs in the family I think mine fluctuates too much
Why do you drink so much water? Are you incredibly thirsty? If you are that thirsty I would suspect diabetes. If your blood sugar is out of whack it could cause some of the symptoms you are talking about. Also, I would see if a doctor can rule out Thyroid problems or certain types of epilepsy. I wish you better health.
Going to a neurologist would be wise- they may want to order a brain scan and possibly an EEG as well with your symptoms.
Additionally, I am strongly suspecting you may be suffering from water toxicity given the amount of fluid you say you are taking in. Water toxicity can lead to an electrolyte imbalance in your body, cause seizures and be deadly. Too low of sodium caused by water intoxication might also explain the syncope (fainting).
Please be sure and cut back your fluid intake tremendously- think 48 ounces per day up to a maximum when you have a virus or infection of 80 ounces per day. Talk with your nephrologist (I hope you do have a kidney doctor since you have only one kidney?) about your situation also.
Getting a copy of your medical records is a great idea! If you can organize them in a folder, they can be pretty easy to lay your hands on when you are planning to visit a doctor... you can have them at your fingertips anywhere you go. You'll want to make sure if they look at them you get your copies back so you don't have to start over in getting more copies, which I imagine might cost some money?
If you don't have one already, please buy a blood pressure monitor from the store. The instructions on them are quite simple and you can learn if you are having high blood pressure readings frequently or not at home that way. Hypertension is definitely something to watch for if you have a lowered glomerular filtration rate (GFR) with your one kidney. Also, if you do, avoiding NSAIDs such as ibuprofen I believe is generally advised too (have a sibling with two kidneys, but one is congenitally defective)- you probably already know that about NSAIDs.
There is a way you can do the "poor man's tilt table" test at home. Use a blood pressure cuff that also takes your pulse. Omron is generally a good brand if you can get one of those.
Take your pulse or have someone do it that knows how- that's in case the monitor gets the pulse wrong (sometimes they seem better for the blood pressure than the pulse reading). Lay down for about ten minutes. Take your blood pressure and pulse with the monitor & then take your pulse in your wrist. Then stand up. Wait a full minute and take your pulse, etc. again. If your pulse is more than 30 beats a minute faster standing than it is when you are lying down, you might even remain standing and take it again after you've been standing five minutes. Record the numbers and show them to your doctor you and ask if you could be referred to an electrophysiologist for a REAL tilt table test. Another test that might be done to confirm P.O.T.S. is a standing plasma norepinephrine test.
If you learn you have any form of dysautonomia, including if you have P.O.T.S., as I do, feel free to join the dysautonomia forum here on medhelp and ask questions! Here's a link:
http://www.medhelp.org/forums/Dysautonomia-Autonomic-Dysfunction/show/266