Do I have anorexia?

I I havent been eating enough lately, in fact I havent had lunch in 3 days. I dont count calories, but when I weigh myself and Im over [edited by 24Help1 5/24/20 for specific weight] lbs (Im 13) I freak out and start to restrict foods, but recently I havent been over [edited by 24Help1 5/24/20 for specific weight] lbs and I keep eating things, feeling bad about it, and then burning off more than I needed to. I get pains in my chest which I dont know what that means but I have them, and at the doctors office Im always underweight. Theyve always said I have a great metabolism, which makes my situation even worse considering I dont gain a lot of weight. I havent told anyone except people on 7Cups because I think Im just overreacting, but now I think its getting serious. Problem is, my parents dont know because I dont think theyll believe me because I have depression AND insomnia already. Ive also taken 5 online anorexia tests and they all came out saying I could have anorexia. Tell me what you think as soon as you can, Im scared.