My sister is mad at me :'(?

I think we need to hear both sides of the story before deciding who is right and who is wrong. However, from what I have heard I think your sister might be feeling a little left out from getting not as good prezzies as you. I think you need to be supportive, whenever my sister is upset with me, I go to her room give her a mage, and ask her what she wants (e.g a prezzie) then if the slagging continues I'll go to my mum and tell her everything i've done (e.g been supportive) and tell her my point of view of the story. Don't worry, its just a hormonal thing, she'll be over it tomorrow. Good luck