Why is my body not hydrated enough?

I've decided to become more health conscious and to get in better shape. I'm 16 am 5 foot 6 and 145 lbs. I'm not fat at all. I just really want to tone up and be more athletically fit. I've been jogging and running at sunset so it's not too hot and I drink nothing but water. I have a camelbak full of water about every 1.5 hours. Like clockwork though I have to pee in 20 minutes of finishing it. My skin is dry still (not like anything bad, just requiring a little bit of lotion), but I thought that when you drink a lot of water your skin in naturally hydrated. Am I drinking too much? Should I have to pee so often? Why is my skin still dry? Curious