Recovering anorexic - how do I gain weight easily as to not get in trouble?

I am currently recovering from a severe case of anorexia, and I have a nutritionist appointment tomorrow. My goal this past week was to maintain my current weight, but I got a really bad case of the stomach flu - and lost 3 lbs. I get a consequence if I lose weight, especially this much, but I honestly only lost it because of my bug. I've followed my entire meal plan (which is big) and more today, but I'm super hypermetabolic - is there any way that I can gain at least a pound by tomorrow??