This is for Endoh-chan, Cherry-chan, and Monserrat-chan. I know that Monserrat-chan and Endoh-chan are teenagers, and I don't know what Cherry-chan's age is so I'm also assuming that Cherry-chan is also a teenager. If I'm wrong, please correct me.
As you all know my major in college is Education to become an elementary teacher, but I'm also getting my minor in Psycology (Study of the human mind). Before I begin, I hope I don't sound like a know-it-all, and am talking down to you. I apologise ahead of time. Also, don't tell your parents. I don't want any of you to get in trouble because of what I said.
I'm 22 and I remember what it was like to be a teenager. It su**s, I know, but the worst thing about it was how the relationship with my mother changed. I used to be able to talk to her, and tell her my problems, but the minute I turned 13, I became a kaijuu. I was he** on earth.
For Monserrat-chan, you stated that your relationship with your mother changed, and she favors your little sister instead. I know how that feels, only it was with my older sister. I'm the youngest in my family. Your mom is not made at you. Chances are, she's actually scared now that you are a teenager, and I'm also assuming you're the oldest.
Again, if I'm wrong, please correct me. But in the case that I am right, you are her first child that is growing up and becoming a young woman. She doesn't know what to do. Please be patient, and though it seems hard, try to listen to her, and help her. It will be difficult, but it won't last. Show her your love and hopefully she'll calm down.
The above was also for Cherry-chan. Again, if I'm wrong on any of my assumptions, please correct me.
And as for Endoh-chan, if our lives are as alike as I think they are, chances are your mom and dad are frustrated with your brother because they can't control him, and they choose to take it out on you. My parents did the same thing to me. The good news though, they realized what my brother was really like, and now that he's gone, they eased up on me. Be patient; things will turn around.
And this is for everybody: Zettai Daijobu Daioh! (Everything Will Definately be Alright!) I can guarantee, things will change for the better. It seems hopeless now, but things will definately change for the better!