I've had flu like symptoms and every time I cough or sneeze, I urinate. I started noticing here lately that my urine is brown. I drink a ton of water.?

Urination. It could be something as simple as dehydration causing a change in color of your urine, however there are certain kidney diseases that occur during or after flu/upper respiratory illnesses that need to be ruled out. Iga nephropathy and post strep glomerulonephritis are key. You should see your primary doctor and have urine tested for blood and have your blood tested to see how your kidneys are.