Please, please read this..

1)
Is there a counselor at school you can talk to? That might be a good place to start.

2)
5 ft and 110 lbs is not fat --- 5 ft 3 and 123 is not fat
both of these weights fall smack dab in the middle of the healthy weight category.
BMI is a guideline that helps you guage an appropriate weight for your height. It's a good starting point.

Your body is a vehicle that you need to get you through your entire life.
Work to make yourself strong enough to dance and swim and hike and kayak and horseback ride and climb trees and do cartwheels anything else you can think of. Feeling strong feels amazing!

Seeing my own Mom's broken body is what motivated me to start watching my health. I've started late in the game. You're young you can build new habits that will improve the rest of your life.

4)
Use MFP to watch that you are getting enough nutrition first and foremost. I want you to be a kickass girl

3)
Be gentle with yourself. Small and consistent changes. You have enough stress in your life. Revamping everything in your life could cause more. It just gives you more SHOULDs to live up to. Look for small changes that you can work into you lifestyle. Every few weeks add a couple more small changes

This is an endurance event. It's not about getting to the finish first, but learning healthy habits that will last you a lifetime. (I know it sounds corny and at your young age your body seems to be able take a lot of abuse, but there are some things that won't show up till later.

Mostly I think "AM I DOING BETTER THAN BEFORE I WAS WATCHING?"
As long as I"m moving in the right direction I make an effort to stick with it.

It someway I feel like I haven't given you enough
In others I feel like I've given you too much.
Anyway I hope there is at least one helpful bit that you'll be able to hold on to.

Good Luck

First of all, I don't think that it is right for people to be telling this possible (child) that it is a bad enviornment and that she needs to leave. Get real. Having a stepdad and a cpl sisters is not a bad thing. You asked if you were being a whiney brat. I would hate to make a judgement call, but it kind of sounds so to me. Sounds like your problem with (possible) anorexia is coming from a poor self image of yourself. I mean come on! Look at the TV and everything else in this world. No wonder we all go around hating how we look. The Mother / Daughter relationship is a very, very complicated one. I assure you, your mother loves you! One day when you are a Mother you will understand this. Her position is not an easy one, she has other children too. I'm sure that you miss being the baby and having her undivided attention, but it's called reality. You are growing and changing, you cannot go backwards. Just try to make the best of what you have. There are people in this world who have it so much worse. There is no such thing as a perfect family. Trust me! Even the ones that you may look at and wish that you were them...it is just a dillusion! We all have crap! It sounds like you have alot on your mind and feelings that you need to express. Love is a two way street. Write your Mom a letter. Go help her do something in the kitchen...whatever! I think we spend way too much time trying to "label" ourelves these days. Come on! If someone makes their bed, we call them OCD! If a child has energy, we call them ADHD! This is insane! I don't know if you are truly anorexic or not, but I can tell you one thing, I believe that if your Mom thought so, she wouldn't be ignoring what you are saying. Most people who are truly anorexic HIDE it! They do not go tell their parents.