There's a zyprexa that causes less weight gain. My Dr wants me on zyprexa too. I told him I'm only willing to go on the one that causes less weight gain. He agreed if this doesn't work that's the next step.
You really want to put together little meals of safe foods, preprep them and set a timer for every 3 or so hours and force them down and to stay down or they will take your options to feed yourself away. Which maybe a good thing for now. That way you see a Dr about all the falling.
There are ways to trick the scales and the Drs but you need the help. You deserve help. I ask that you write a list of everything you don't want to tell pdoc and hand it to them and sit down quietly and wait. You can do this. It's scary, and hard but you can do it.