i read your post and others and think to myself, where did we go wrong?
Fact is i dont think we did, if it was a crime to love your children and do all you could for them then i think we were pretty ok Mom's.
However i think the problem is that maybe we did too much, society nowadays i think (and please forgive me if i sound cynical) is a very much every person for themself world, i have noticed (and i am not blaming myself or others my age) that if you tried to do as much as you could when your children were growing up, they generally only remember the odd bad moment and not the good ones.
i now look back and think, did i give too much of myself? because the Mothers that were always there for their kids seem to be the ones that are treated worst, like yourself.
Your DD seems a very silly girl who is being spiteful to you for no good reason, i cannot see from your post that there is any one particular moment in time where you could say, well maybe that is why my DD is being like that with me, which makes it hard to fix.
As others have said you are doing the right thing concentrating on yourself, good luck with your training and i hope/know you will do well at your studies. Hopefully in time your DD will see how nasty she has been and try rectify it.
I sometimes wonder with all the stories on here, if the very persons who are causing us so much heartache will end up on here because their children have done the same to them that they have done in so many ways to us all, and if so will they then realise that we were all not quite so bad as they think?