weight help SOS

Lately I've been struggling with my eating disorder all over again. I'm 5'7 and 58kgs (was 66kgs) but I didn't achieve this weight healthy, I haven't been eating and now if I want to maintain this weight I need to barely eat (I'm talking maybe an apple a day) I feel so alone and feel like I'm the heaviest for my height. How much should I weigh? Please help me I want to eat but I need someone supportive and understanding as I have no friends