We get this all the time from our july born DD2, she's in year 4.
She's got quite a few ADHD traits, is very emotionally volatile and flies into a temper tantrum easily if things don't go her way.
For most of this year, if we tell her no, or she doesn't get her own way ( Happens a lot with 4 kids!) or something goes badly for her, she'll start a terrible wailing about how we don't love her/ everyone hates her/ she's useless and if she's really upset she'll start head banging or hitting herself.
When she's good, she functions well. Academically, she's doing very well, and she doesn't tantrum at school, just cries if she gets told off etc.
Our eldest DD(9 almost 10) does do the 'you hate me' thing occasionally (once or twice a month) but it's not as convincing as DD2's efforts and with DD2 it's once or twice a DAY.
I just can't decide if it's something to get worked up about and maybe take her to the GP, or whether she'll just grow out of it.
Has anyone got a child like this, and if so, what were they like during the teenage years???!!!