I think you might have a fall back.
I met some family friends a week ago, and met Them a month before that i think and They sad i have gotten pretty skinny Kinda too much even. And They said it multiply times but i dont see that seriously. I eat, not alot but idk really... I exercise pilates pretty much tho, but dont see results and thats what bothering me. My weight is normal for My height and age but i still feel too big. I cant go to groups like that cuz i feel like i dont fit in there, and The rehab center i was in just let med go when My weight was normal so They dont really care i guess...
No, negative calories do not exist, however, some foods have so few calories that it costs more energy to burn them than it would provide. So the digestion costs more calories than the food provides. Some examples:
Apples
Carrots
Pineapples
You may not be comfortable in your body, but are you sure you need to lose weight or do you still have a distorted body image?
You need to, first, determine the weight you need to be for your height and age. If you're not over weight and are still trying to lose weight, you haven't fully recovered from the anorexia.
Maybe all you need to do is firm/tone your muscles, rather than lose weight. In that case, yoga would be the best exercise you can do. In addition to toning/firming, it's also very relaxing and help you accept your body image. As Fruitibiscotti mentioned, find a class near you, at the nearest Y, or other local resource. Some churches, even have classes.
By the way, there is no such thing as eating "negative calories" unless you're starving yourself, which is the last thing you want to do. I think OhMyKittens meant to eat less than you use in exercise.
You are not alone. Remember this...what you have experienced and are experiencing now is not new, as there are others in the same boat as you. Look into joining a post-anorexia group. Look them up in local YWCA or local Meetup groups or other non profit resources available to you. Many groups exists in many cities and towns...like thousands!! At these groups you will meet others in the exact situation you are in. Get yourself a buddy or two from the local group, and help each other get to the healthy weight.
I think you already learned this from the past, that by doing things alone, it don't always lead to success. We all need others to help with learning from each other, coaching each other and sharing winning strategies.
Good luck sweetheart. I hope you find a group (or two or three) to join.
Seems like you are falling back in the arm of Ana. All I can see is do it the healthy way: sports, eating negative calories and of course don't skip any meals.