C.T.
Hi Debra - I dont know that you have anything to worry about yet. Keep on drinking plain water and your thirst will eventually be quenched. If you have any other symptoms like back pain, dizziness, low blood sugar attacks, etc. be sure to talk to your doc. It might not be a bad idea to get your glucose checked. You can always buy some of the sticks that you pass through your urine stream - they can tell you if you are spilling protein and/or sugar into your urine.
The reason I say dont worry yet is because I started making a deliberate effort to increase my plain water intake to between 80-100 oz a day. That's in addition to anything else I might drink that has calories or flavoring/sweeteners, etc. What I noticed is that for a good 2 weeks, I had the worst cottonmouth I've ever experienced even though I was drinking way more than I have in a long while. My PA friend told me that my thirst mechanism was finally working again and now it was just really talking me that I needed to drink.
Plain water does a great job of flushing and cleansing your liver and your kidneys because it passes right through and the liver doesnt need to do anything with it, like if it contained a flavoring or artificial sweetener. The liver has to process those things. As far as the yellow urine - I had exactly the same thing happen this past Monday. I had been taking in around 50-60 oz of water for about 3 weeks (down from 80-90). On Sunday I was back to my goal and I had 84 ounces. On Monday I had 96 oz. Even after drinking all that water for 2 days, on Tuesday morning my urine was still really dark yellow. Finally now on Wednesday, it's a much lighter color. I think I must have just had a lot of junk to clear out of my kidneys.
Sorry about the icky details - I hope my experience helps to calm your nerves a bit