Help: My aunt has told me if I don't eat I have to leave

I (18 F) moved out of my emotionally abusive parent's house last July. And had to move in with my aunt who I barely knew at the time. Since then we've grown really close, but over the past month I've relapsed in my ED and nows she's told me that if I don't eat I have to move out. And it's not a little bit, she expects me to eat at least 2 full meals per day. She said its unfair on her and my cousins to do this to them and she doesn't want her children getting hurt (F19 & M 23). Firstly I am really fucking scared of calories and have no idea how I'm gonna manage that amount of food per day. And second I am devastated that she would give me this ultimatum. I feel like I don't belong here now. She doesn't believe I have an ED as psych have never officially diagnosed me and she thinks its just a choice not to eat. Please can someone give me some advice on the situation!