I suspect it's a combination of a lot of things. She's had a lot to deal with these last few months.
We've left her dad, who used to bully her, relentlessly. She's then had to hear that she probably wasn't going to get to go London, because with leaving our finances had changed and we couldn't afford it. It must have been devastating for her when her dad then turned around and told us he was going abroad for a week in October, after claiming that he couldn't afford to help pay towards her school trip. We managed it in the end, but dd1 is aware that it was her extended family who stepped up in the end and not her dad.
We didn't deliberately tell her this. She was in the room when he told me he was going away. She'd already asked him if he could help pay for her trip and he'd already told her he was skint. She's not stupid, she knows it costs far more to fly to Spain for the week than her school trip would have cost. We did tell her who had paid towards her trip, so that she could thank them, so she does know that her own father didn't pay a penny, but this wasn't told to her out of spite. No one pointed out that he hadn't paid, we just told her who had given us money towards it.
Obviously leaving her dad has meant she's had to move house. We had to leave most of our belongings behind. For many weeks he refused to allow her to take her laptop here, despite the fact that she paid the initial deposit with her Christmas and birthday money. He paid for the other half you see and deserves to have a laptop. We've sorted that now, he now has dd2's laptop which is worth far less and is more easily replaceable. But having to leave behind your most treasured possessions, that you saved hard for at only 10 years old must have been very hard for her.
He took my phone back which she'd been asking for, when she pointed out that she was told she could have it and had been waiting 2 years for it, he told her it was tough, he paid for it, he decides who should have it. He refused to give her his old phone or any money towards a new phone. (she's getting one for her birthday)
Now she's allowed friends around, they've started inviting her to their houses. She's met their dads. She seems to have been surprised at how little their fathers shout at them. Her friends won't come here if her dad is here for anything because they are scared of him 
She's told him this, he's told her that is their problem.
I've also found out she's been asking my mum about her bio dad, who has never bothered with her before, she's never met him. She's always been aware of him, we've never hidden the truth from her, but she's never wanted to know more before.
And on top of that she was over tired, hungry and probably hormonal and is developing breasts, which she seems to want to try and hide and deny.
I think she is feeling understandably confused and tender right now, so her tantrums are getting a little bit more tolerated than they normally would be.
She's still not getting a new charger though. She failed bedroom check yesterday, which means no pocket money for a week. She'll have to wait until next week.