I'm out of my depth with my 6 year old dd behaviour and really need some advice 
I love her to bits but she is becoming very selfish and rude and displaying "unlikeable" behaviour . I don't know how to handle it .
I know she sees my frustration when she acts this way and I try to praise even the tiniest good thing she does , but it's never enough for her - she always wants more . Of everything !
Examples :
I had surgery last week and I use crutches at the minute . On the way to school today I asked her to carry her own bag (I usually do it as she likes to run) . She huffed and puffed , spoke to me rudely , complained the whole short walk there and asked why she had to do everything 
I explained that as I was poorly at the minute, she needed to help .
She has a real problem with sharing - toys and food mainly . Her little sister always offers her food but dd1 refuses to do the same .
If her sister comes out of school with a biscuit she's baked DD1 is in her face telling her if she doesn't half it she won't ever be her friend again 
As dd1 won't share , it got to the point I told dd2 not to bother sharing either .
Both girls had a packet of crisps - we have been trying to encourage dd1 to offer things to other people (dd2 does this naturally) . Dd1 offered her sister and her dad a crisp - both took one .
Dd2 then offered dd1 a crisp - who sneakily took two then denied it and finally admitted she did because she had "lost two" and it wasn't fair !
She's starting to lie about silly things .
I thought she might need some one to one attention . Dd1 loves colouring. I told her I was ordering myself some adult colouring books and I'd love it if we could colour them in together . She was pleased - until she asked if the colouring books could be both of ours .
I explained they were mine but I'd love to share them with her and she can help me anytime . No. She wasn't happy - she wanted them to be hers too.
She also complained that I'm important and everyone is looking after me just because I've had surgery .
Her behaviour is exasperating and it goes on and on and on over every little thing .
Please help ! 