Sleeping schedule fucked up / Insomnia

As I enter finals week the worst thing possible is happening to me. I no longer want to sleep after long periods of time and when I do go to sleep i wake up far into the next day. It is Saturday and I just woke up at 4:30PM. I need to break this habit and go to sleep like a normal person. The worst part of it all is that when I do wake up I can't remember a damn thing that happened the night before, its like a hangover without realizing I got a random girl pregnant.