Please help me.

I am feeling so sad and mad right now and I can't (and don't want to) hide it from my family but I know it's not right to ruin Christmas for everyone else and the reason is so stupid and shallow that I'm feeling ashamed to write about it in an anonymous post.

I'm mad about presents. Like a child. And I'm not a child.

So two days ago I went shopping for clothes with mom and sister. It was the present I asked for to my parents.
Mom gets me and sister more or less the same amount of clothes.
All good, everyone is happy.

Skip to today: I get my clothes, no surprises but I'm glad. Sister opens her presents: the clothes and an iphone 6.

I know I have no right to be mad, and I'm honestly happy about what I got since I need them but I can't help but feeling like a b-series daughter. 

Please help me get out of this feelings of hate and sadness before I go full Grinch on my family. 