We are on holiday at the moment but it doesn't feel like it because of 13 year old dd's terrible moods.
She is the youngest of three girls, dd1 more or less sailed through the teenage phase so this is all new to us. Dd2 has always been more emotional anyway but in the past six months she has really changed and has lots of mood swings, crying fits and strops, snaps at me and dh and her sisters, starts arguments and refuses to let things go. I've got the book 'get out of my life etc....' and it's as if she's read it!
She knows she's doing this and can't help it and actually dislikes HERSELF when she's like this.
So we're 5 days into a 2 week holiday. Most days she has been sullen and unpleasant for some of the time. Yesterday we were at a particular attraction and her phone camera wasn't working which resulted in a huge over reaction and tears etc which lasted a couple of hours.
I say to dh and to her sisters that however bad it is for us, it's worse for her so we're trying to be sympathetic. But it's very very hard and I wonder if we should be firmer when she's making an atmosphere. Today she hit her older sister because she got cross with her for laughing. I told her off good and proper for that, there is no excuse for physical violence.
I often get the brunt of it - I 'have a go at her', speak in a patronising way, look at her wrong etc. I'm just so drained with it all, I can't help wishing it's just me and dh on this lovely holiday which cost a lot of money 
So what's the best way to deal with this and how hard should I be? Is trying to ignore it the best course of action? And offer hugs and sympathy when needed? Or be firmer with her for attitude and nastiness towards others?