QMy parents treat me like I'm 5 years old and I'm 15. And my brother gets all the attention now and everybody thinks he's all mighty. They treat him like a saint and me like a germ or something. I just got yelled at because my brother and his best friend were yelling at me and calling me a brat and all. My mom came in and started yelling at me as if I started everything. And then my step-dad came in and yelled at me, too. My mom always does this to me and I hate it. It's as if everything that goes wrong in the house is my fault and then I get yelled at for it. And whenever my brother and or his friends do something to me and I tell my mom (I'm not a tattle-tale) she tells me to shut up or go away. It's like she doesn't care if they hurt me.
I was going to suggest that you get them all together, like at dinner or something, since it involves the whole family, but then I realized that might not be such a good idea, since it would be easy for one of them to dismiss your concerns (as they've been doing it seems) and then for the rest of the family to just follow along with that.
So, I suggest that you talk to them individually. For instance, when your mom or step-dad are doing something alone around the house, such as laundry or dishes, and they are in a relatively good mood, start helping them and say, "Mom (or your step-dad), something's been bothering me, and I'd really like to discuss it with you, and I want you to take me seriously." If you start by talking to your mom, tell her that you are going to discuss it with your step-dad as well, or vice-versa.
But it sounds like your family could definitely benefit from some intervention from a family counselor - sometimes families get into ruts and they need help to reframe things, and to make families realize the roles they've been playing.
See if your parents are up for it. If not, why not seek out some counseling for yourself? Maybe a counselor could give you some good suggestions on how to deal with this...
I hope my suggestions have helped.