It is very difficult, but it can be done with careful planning and a good support system. I suffered from eating disorders for years and was finally sent to a treatment program 4 years ago. After treatment is when I gained all the weight. Having an eating disorder is really a life long struggle and some days are really hard. I make sure to talk a lot with loved ones about my weight loss efforts and have people who watch me closely and who aren't afraid to confront me when I start exhibiting ED behavior. I try and be very honest with my day to day feelings about my body and try not to hide anything. A few times people have had to tell me when I was falling back into habits(I've had my scale taken away before by my best friend and boyfriend). I do a lot of self monitoring and use all the advice and lessons I learned in treatment to help me stay healthy.
Have you talked with a health care professional regarding your history of ED and could they help you with staying safe? or maybe you could get a referral to a therapist who specializes with ED clients? Is your family aware of your past and do you feel comfortable asking them or friends to help monitor you?
I wish you the best of luck and hope this has been helpful! I know its really hard, but it can be done if you are careful