recovering from an eating disorder?

I'm 15 years old and I've been battling an eating disorder for a few months now without even knowing it. I cut out a lot of things and have been living off of 600-700 calories a day. That to me sounds like enough, because I do eat as much as I think is enough which is 3x a day like any other person, I just eat in moderation and I eat low calorie foods. It's been brought to my attention by family and friends that I've lost too much weight, but I don't exactly know what to do. It's so simple for them to say just eat more but they don't understand how difficult it is for me. I could just get up and start eating but I heard that just changing my eating drastically like that will make me gain more weight and at this point I just want to maintain it.

I'm 5'6 and weight 133 pounds.

For reference, I used to work out about 5 times a week but now I've cut it down to 3 (but that's when I was trying to loose weight which I'm not anymore)

What are ways I can slowly recover without gaining weight and what are tips to maintain my weight?