[ElsatheDepressionSlayer]

I think you should definitely tell a teacher. Most of them are pretty well-equipped to talk about these sorts of things.

Dez pretty much said everything in her post, but I just want to add this: My dad's a teacher and he says that students come to him with their problems all the time. There are more of your peers going through rough times than you would think, so teachers know how to handle these situations.