I had a small baby at 31 weeks, and was also very thin. I can't remember how much weight I'd put on, but really was off food. Anyway, they scanned twice a week (for fluid levels as well), and eventually decided the baby was stopping growing. I was pulled into hospital for a week and monitored twice a day, then induced at 35 weeks. He spent a few days in SCBU till he could suck for himself, but was totally healthy.
They said at 31 weeks that the lungs were fully formed, so I didn't need to worry if he came any time from then on, but they managed to string it out a bit longer.
Remember, lots of babies are just 'small because that's how they are', not because anything's wrong. It's a good thing you're having these scans - it means the hospital is on the ball and if it stops growing they'll manage it.
I have another routine growth scan in a few weeks - It sounds mad, but I'm more worried about childcare if I get pulled into hospital than I am about the baby not being OK even if it's looking small. I know the hospital will have this under control, and the baby will soon be big enough to do well even if it's a bit early.
Sorry you're struggling so much to eat - are any of : crisps, plain biscuits, orange juice or bananas any use? They're my pick-me-ups when I'm feeling really weak. The other thing I notice with medication is that I feel more drugged and ill when I'm not eating much, and actually have less side effects when I'm eating more. I don't know why though.
Hope you feel better soon and Monday goes well
x