In my opinion, if it happens, it happens. My parents split up, for my family I think it was a good decision for them to break up. They would have continuous fights and there was nothing to stop them, it would keep going. If they would have stayed together, I would just go through more and more pain than them going their separate ways. There really is nothing you can do about it. It is their decision to split apart if they do, it is their relationship... but keep positive.
In my opinion, you should look for time and explain to them that the fighting is affecting you in a big way. You could also talk to a counselor in school or a close relative. Be positive that a divorce won't happen.
Bummer, its a hard time right now with the family, What you can do is try to do better about being lazy, you don't have to fix this yourself, but you can help out extra when it's a rough time. A house divided can not stand. Things change and it can get better. Show you'll do your part for peace.