Eating disorder?

Patient: Hey,I’m worried that I may have developed an eating disorder, but I’m not sure if it’s just me overanalysing it as I can’t find anything on the internet about it.Basically, for the past couple of months I’ve been eating as much food as I can on the weekends but then during the week, I only have a very small amount of food and a daily coffee.It started off almost accidentally as I didn’t have the money to afford food for a week, so I ate virtually nothing, and then when my pay came through on friday, I stuffed my face with as much food as I could find.The next day I weighed myself and I had lost about 5 pounds. I wasn’t the fattest person in the world in the first place, but I definately looked more trimmed.After looking thinner I didn’t want to put the weight back on, so I did the same thing the next week, and then the next week etc. now I can’t stop and I think it’s affecting my life;I’m constantly feeling weak, tired and more recently, I’ve had pretty consistant diarrhea.My sister was hospitalised with Anorexia about three years ago and I’ve been in a psychiatric hospital about two years ago where I shared a wing with the eating disorder unit, So I like to think I know quite a bit about the subject, but I’ve never heard of anything like this.I’m not too sure what’s happening?