Peeing Frequently??

usually when i have to get up for school or work I can go the whole day without having to pee and not be bothered but when it's a weekend day and I sleep in I'll wake up the first time and have to pee, which is normal, but then almost like clockwork I wake up every two hours to pee until i get up for good. And I'm not talking about just a little or an urge to go, it's like a regular pee, Sometimes I do drink a lot of liquids before i go to bed but after like the first two times shouldn't i have cleared my bladder out?