What should I do about my friends? HELP ME PLEASE!?

Ok, so I go to an all girls grammar school, so there's loads more b*****s than you'd find in a normal school. Two of my friends have started arguing there's four of us so I'll give us names : I'll be Bobbette, then they can be freda, creda and linda. Me and linda went to primary school together and we were inseparable,we still are. But freda and creda have got into a pointless argument over nothing, its been going for 3-4 months now and it drives me insane. I get really, really upset, I keep crying and sometimes I get angry and hurt myself. I think about ditching them, but how would I do that without linda? She doesn't mind them arguing, as long as she herself has friends but i would rather they hated me than hated each other. I wouldn't have anywhere to go. Apparently me feeling just a little bit suicidal isn't important enough for them to even TRY to stop bickering over nothing, that's right in four months, they haven't even tried. It's not just me, everyone in our form thinks they're being ridiculous. This one girl noticed I was really sad and asked me why, when I told her she sighed and was like are they STILL arguing? that's so stupid they've been going on about nothing since november! Its their birthdays soon and I know how I'm gonna feel. So what can I possibly do?