First off there is nothing physical that is making it so that you can't really stop. It is a choice you are making

Loosing all that weight you got rid of from the meds can end up being almost an addictive feeling. I know my MIL who didn't ever have an ED was on a diet & lost this huge amount of weight & she couldn't stop loosing once she got started.....& I have felt that feeling when I was actually on a med that caused me to loose my appetite & then again when I was under a huge amount of stress (which I was also under when the meds caused me to loose my appetite also.

What you HAVE to do is to increase the mount in food you are eating JUST ENOUGH to balance out your weight at the weight that is your perfect weight. It's difficult to force ones self to do anything but it's just as possible as doing nothing. Some choices we HAVE TO MAKE because the consequences otherwise can be life threatening.