Your symptoms suggest something to do with the kidneys.
In fact, some people who have been badly hurt
in a
war situation, their muscle tissue at the site of injury will deteriorate, and when the breakdown passes through the kidneys, it can cause the dark urine. But there are other causes, including an infection or dehydration. One simple thing you can do to help whatever the diagnosis turns out to be is to drink extra water. And if they've already done a urinalysis, get another one.