I can well remember those days.  I was very dramatic as well.  There were also adult issues I had to deal with at a young age but not losing a parent thankfully.  I can tell you what not to do.  Don't pass her off as silly or hormonal..even if that is the case.  Listen, be patient.  Don't push some pharmacteutical prescription drugs on her either. That just masks the problem and makes her feel like a problem.  Maybe a grief counselor, if you feel she needs it.

Get involved in church, recreational activities and/or family activities to buid her spirits. I would be genuine but compliment her often.  Be an open ear, but let e know you dont wish to be disrespected either.

 I can give advice easily because mine is only 2 now. ;)

Good luck!  You can do it!

My sister is 9 years younger then may and we all grew up with my Dad and I have seen my dad been ripped to shreds by my sister on several occassions whilst going through her teens. She is now 17 and has settled down a lot. I think the best thing is to talk to her a lot, and let her know that you are there for a chat. I remember myself that teen age years were hard because your too young to do adult stuf but to old to do the kiddy stuff. She will work it out as long as she knows you are there for when she does want someone to talk to. Just trust her and give her a little space.

I am having similar issues with my 11 y.o. I rang the health food store and spoke to the Naturopath and he recommended I get an omega 3 supplement like fish oil or flax seed and one with B complex vitamins in it to help with the mood swings. I hug her when she needs it, be a little more tactful and stand on her for being out of line. Just because she is suffering doesnt mean she can be rude or disrespectful.

Sorry I couldnt help more but at least you know she isnt the only monster out there.