Welcome back :)
It really does sound like you're in a bad headspace food-wise and going about weight loss in this manner is never going to end in happiness I'm afraid. What was your experience of living with family members who had eating disorders? I'm wondering if some of the negatives you saw might be helpful in getting you to refocus a little and have healthier goals. Perhaps it would be helpful for you to think about what the feelings are behind wanting to be underweight and to pass out from lack of food; why are these appealing to you? Yes it's not healthy to be thinking in this way, but you don't need to judge yourself because of it; it's not your fault that you're in a really disordered mindset about food and your body.
Do you have any professional help at the moment? It sounds like you could really do with some input at the moment.
The ED rules actually changed ten years ago, so you may well have read them before, but
here they are, just in case.