Whatever you do, DO NOT DRINK URINE. People who suggest this, including a example I saw on a survival show, are just plain wrong.
The job of your kidneys is to take out the trash. This trash is in the form of various chemicals that are biproducts of other parts of the body doing their jobs. Energy is delivered to cells chemically. Cells take in chemicals that combined are in a high-energy state. They re-arrange these chemically into a low energy state, thereby deriving energy for themselves that they use for various life processes. The resultant low energy chemicals are the trash they just eventually dump into the blood stream. The kidneys are constantly grabbing these trash molecules from the bloodstream to keep it clean. Without kidneys, the trash builds up, which will kill you in a few days.
Like a lot of similar industrial processes, the kidneys use water to move the trash and to keep it in a solution such that it can be more easily handled. That solution is urine. If you drink urine, you are putting the trash back into your body, which the kidneys then have to expell again, again using water in the process. In fact, the kidneys require energy to pump these trash molecules out of the bloodstream, which makes some amount of additional trash, which takes additional water to get rid of. Therefore drinking urine will cause you to loose water overall, not to mention the added stress on the kidneys from having to take out the same trash twice, especially when there is less than usual water available (you are already dehydrated).
Urine is mostly water, so if you can somehow purify it, then you can drink it. There are ways to purify water in the wild, so you could conceivably use urine as a water source, but only if you are able to purify it. This is really no different from using seawater as a water souce, and the backcountry methods for purification are the same.
If you can build a fire and have suitable closed containers and something you can rig up as a condenser, then you can distill urine to get mostly clean water that will provide net hyderation to drink. Without a still setup, you can use solar condensators and the like. You don't need to boil a mostly-water solution to generate (mostly) pure vapor, just that you get a lot more of it more quickly that way. Any method that keeps the original liquid at a higher temperature than the output in a closed space will eventually condense clean water. It's a bit of a aside, so getting into details of such methods is too much for this post. But it can be done, although passive condenstation produces clean water only slowly.