You are doing serious damage to your kidneys by not drinking more water. All kinds of serious diseases can come from your body being dehydrated.
It will be hard at first, but start drinking at least 8 8 oz. of water daily. After awhile, you will be so used to it, your body will tell you when it needs more water. You will also notice that you aren't as tired and your skin will be hydrated and look fresh and new!