Complainer

I'm going to be a bit of a complainer right now.  I'm sorry but this is just a place for me to get things out.  Also anyone with a stepsister please HELP!!  She is one of the most confusing people I have ever met in my life!!  One minute she is happy and the next she's angry.  I am constantly having to be aware of things I say.  Whenever I try to talk to my step mom about it, it seems like she always takes her side because that's her daughter.  I feel left out all the time, and like it's just a game to my stepsister.  Like lets see how pissed we can make Mae today. I know I have a BUNCH of flaws to and I'm working really hard on them.  It just seems like I'm not getting anything in return.