Some chemical reactions in your metabolism release tiny amounts of visible photons. In 2009, researchers photographed this glow in total darkness using ultra-sensitive cameras: about a thousand times too weak for the eye, it was strongest on the face and varied over the day. You literally shine, just very discreetly.
Every day, your kidneys filter around 180 liters of blood plasma, about a bathtub's worth. Yet you only have about 3 liters of plasma, so it passes through your kidneys some sixty times a day. Over 99% of the filtered water is reabsorbed, leaving just one to two liters of urine.
A 70 kg adult is made of about 7 × 10²⁷ atoms, or seven billion billion billion. The observable universe is thought to hold on the order of 10²² to 10²⁴ stars. Even with the high estimate, you contain thousands of times more atoms than there are stars in the entire visible cosmos.