Another day, and your family is still fighting. Another day of sadness and anger. There's always a way to deal with the problems.

[edit] Steps

Realize what the problem is and think of possible solutions to it.
Talk to your family about what is occurring and how it could be fixed of eased.
Even if no one listens to you don't do anything you may regret later. This includes self-harming and threatening to commit suicide
Even though it is hard, talk to ANYONE that will listen to you vent.Try talking to someone you trust in school, like a teacher or a counselor
Remember no matter what happens, if the problems can't be solved it is never your fault.
Don't beat yourself up over something that's your fault. You are a good person, no matter what anybody says or thinks.

[edit] Tips

It may be hard but talking to people will help you get some of your emotions out so that your not bottling them up inside.
You really are a great person, even if you don't think so, find a quiet and safe place that you can go to and think or read or do whatever relaxes you, like a place nobody but you knows your at.
There are other people out there with the same problems (me, as an example) and the ones who have overcome it want to help you.
Never give up.