Do I have an eating disorder?

I have always wanted to be skinnier my whole life, but recently things are different and i have an intense urge to lose alot of weight. I avoid scales to weight myself. I eat alone at home becaue i am afraid i will be made fun of. I have been slowly eating less and less. I have been on and off fasting. When i finally am so hungry, and i eat alot i throw it up. I hate my weight. I avoid swimsuits. I drink water to keep me full. I read diet/fitness magazines daily. At scool when ido decide to eat, i am embrassed of myself when people look at my tray whether it is full or empty. i workout alot. I suck in all day. My actual dieting consists of skipping meals, eating once a day, throwing up. and if i do eat and do not puke it up i feel guilty and fat. I cry everynight because of my weight.