Do I have an eating disorder?

Okay so I think I may have EDNOS (eating disorder not otherwise specified). I have been obsessed with my weight and my appearance for about a year now. I also feel worthless all the time. I use food as a way to control my life and make it better in the future. Here's an example of a week's diet. For the first four days I would limit myself to 500 calories a day, but then I would be so hungry on the fifth day that I end up eating about 3000-3500 maybe and then I feel guilty. I try to purge, I can't though, I managed to puke out a little bit of food the other day but not much. I sometimes excersize excessively to try and burn the food off. I lost weight last year by eating a healthy 1200 calories and I became really skinny but I didn't think I was skinny, I thought I still looked the same, even when everyone was telling me I was too thin. I eventually believed them I decided to eat back to normal again. My mother later on told me I had gained weight but she meant it in a nice way. I was so shocked because whenever i here the word 'weight gain' i think of fat. I got depressed because I thought I was big and I began to binge eat so much. Anorexia symptoms then came after that but I still binge at times and feel like sh** afterwards:/. I wish I could enjoy food and have a good relationship with it but I can't. I also always eat healthy foods because I want to care for my body but when I binge I can't stop myself and I have to eat lots of sugar. I always see food as an enemy. I never socialise because I'm worried about what people think of me and what boys I know would say. I hate leaving the house. I'm so alone. All I have is my school work to keep my mind off things. What doesn't help is that I only live with my mum. My dad lives in darby and he has a new family now and he's getting married to his girlfriend next year. He sees me every fortnight but I want him home with mum. My brother is at university so I only see him in the holidays. They are the times I feel happier.. I'm 15.. I'm still young.. and I just want to get my life back on track again:/