The border traverses a variety of terrains, ranging from major urban areas to uninhabitable deserts. Approximately 350 million legal crossings occur annually, and is the most frequently crossed border in the world. The total length of the continental border is 1,954 miles (3,145 km).
Only a veterinarian will know what's wrong with your dog but usually stumbling, wobbling and falling down is associated with neurological problems, especially if there aren't any other signs. I would really take him to the vet as soon as you can.
Taking it for a walk around the block guarantees the dog will want to pee. Have you ever noticed how people avoid you when you have a urine cup, and you're collecting a specimen. Some dogs won't pee, and you have to run them down the road, then when they get in position again, you squat down and collect the specimen. They want something less than 2 hours, much less.