20w+3d possibly bed rest... need advice

Katelyn
Okay ladies. I'm 20 weeks and 3 days. I've lost well over 35 pounds so far during my pregnancy due to morning sickness and diarrhea.. 
my baby girl is healthy as far as my doctors are telling me. 
But I was told if I don't gain weight by the 27th of Sep. I was going to be put on bed rest and have a nurse at my house everyday giving me ivs and medication.. 
I eat non stop it feels like but then I get hit with the bad vomiting and diarrhea, and it seem to not matter what I eat or what medicine they give me to help stop the vomiting.... 
Does anyone have any advice as to what I could try to eat that will help me gain weight? I was told to just eat as many calories as I can and not worry about nutrients or stuff like that.  I'm just concerned about my baby's health and my own health. I'm currently on prenatals as well.  HELP PLEASE FTM!! 😬