How to overcome the fear of being alone in the dark...?

For the past week I have not been able to sleep. Thank god it's summer so, i still have the opportunity to sleep during the day. But, other than that I would have to go and lay with my older brother in order to feel safe enough to sleep. When I'm in the dark I get real tense but, once I close my eyes i feel suffocated. The worse thing is my brother is going to a Culinary School in Dallas and will not be back for a week. I can't just stay awake all night and sleep all day. That will mess up my schedule and after 12 everyone else falls asleep. I'd just be awake in the dark and paranoid with no one to keep me busy. I know this is a lot of detail but, I really need Help. I'm 15 and definitely don't want this to be a problem like it's been. Once school starts up i'm going to be taking AP classes. I need my sleep. Please anyone at all, help.