Can you die from being sad all the time?

I seem to be sad all the time mainly feeling sorry for myself this is a hard question to ask because, I'm only 13 but, I have gone throw alot. I seem to always be sad and crying about somthing and I don't mean somthing like not getting my way I mean because, of stuff people my age should not have to deal with. My mom is the only one at home when I get out of school and we always get into some argument and my grandpa pasted away last June and even more bad stuff that I can't talk about, I'm eating right and am really happy at school with all my friends I'm not over wieght or anerexic, not abused, just alot of yelling. I can have an atitde some times but, I really don't talk much or have much expression even anymore. I think about running away and killing myself alot, I know I would never ever ever... do any of that I'm to wimpy and know it would not help but, I just don't know what to do any more.Please tell me if I don't hurt myself but, feel like this all the time what will happen?