Oh dear! I hope you get good food soon! Again, I always recommend bananas and applesauce for upset stomach if you're throwing up, and add some drink with electrolytes, like Gatorade (although I'm sure there are healthier drinks). If it's C, then make it regular apples. This is part of the BRAT diet. Rice might be good too. If you are struggling with oats, it's very possible you could have a gluten intolerance or even Celiac. So, in that case I wouldn't advise the toast from BRAT unless it's gluten free bread.
I'm so concerned for you! I really hope you start feeling better! Much love!

And as for the friend thing, maybe just explain you are having stomach issues...i dunno. Sounds like a tough situation and you want to be a good friend, but your health is being compromised here. I worry that you are worrying too much and that's making your stomach issues worse. I know it does that for me, so I can only imagine.

Again, much love and hugs!