Am I possibly anorexic?

[Rubbishheap]

Hello, I've been wondering this for awhile. I am a 15 year old girl who has had her period for 3 years now, however, I only get it every 3 to 4 months. I also mainly get most of my calories I've realized from sugary drinks. For my meals during the day: I do not eat breakfast, I only have a cup of tea then I head to school. Then, for lunch, I rarely eat lunch, if I do, it's only a 126 calorie yogurt and a sugary drink that is worth about 140 calories a can I think. Then when I get home, I have more tea and then for dinner have child like portions (like 4 chicken nuggets and maybe occasionally a few chips). For my weight, I'm the skinniest person in my family as most females from my mother's side is apple shaped and the women from my father's side are relatively thin. I am 90 lb (6 stone 4 lb) and have been trying to gain weight due to my family and friends getting severely worried for me. Now, some background info, in 5th grade when I was about 12, I was 30lb and I think it was a cause from a sickness I had when I was in first grade where I couldn't eat or else I would throw up blood or whatever, they never found out what it was but it lasted a bit more than a month and I couldn't eat much else other than orange juice or the occasional apple sauce. Besides the point, I'm just getting a bit worried and was wondering if I need to seek more help. Thanks to whoever takes the time to read this pile of words and answers me honestly!
(I'm sorry for any mistakes I might've made, English isn't my first language.)

[cl0119]

anorexia is a mental disease not a physical one. it is characterized by distorted body image (thinking you're obese when you're underweight), fixation on weight loss, and obsession of counting calories.