Its never a good idea to physically harm yourself, such as cutting, so NEVER do that. But 90% of all teenagers will have had thoughts of suicide by the time they turn 18, so thats not all such a bad thing, but it is not good to act them out. A good way to help is mend fences, if there is anyone at school you dislike try and get back on their goodside, and this may sound kind of corny or whatever, but try and get a boyfriend/girlfriend.