Hey bud,
If you aren't depressed, and you're just having a bad week or month, then all I can say is hang in there and take the advice that some of the other people have posted.
If you are depressed, then I can say that you've already begun to do the most important thing, which is talk about it with other people. I can't speak to you from my own experience, but I have been hurt badly by an other's depression quite recently, and by far the best, most helpful, and safest thing that you can do is talk to someone about it. Whether that someone is a close friend, a family member, a teacher, or a school counsellor, it's important. They can be an outlet for your feelings, a helping hand, or just someone to watch out for you. No one will cheer you up if they don't know you need it, and if you talk to anyone who isn't a complete douchebag, they will definitely make an effort to help you out.
Anyways, make sure you talk to someone, and not just on the internet, but someone you can see face-to-face. The worst thing you can do with your problems is hide them, because they won't just hurt you, they'll hurt all of the people around you.