Tired of being tired

So for the past three or so nights I just cannot get to sleep! I feel so drained and I wish I could just rest for a day but the truth is, I have so many things to study for including PAT's. PAT's are basically a bunch of ginormous tests you take every three years to compare your school to others. But it also counts as your final for the year! So it is hard to rest when there is so much to worry about. My first test is May 11th and the rest don't start til June, I am not sure how to stop worrying about it and I haven't had a decent nights sleep forever!