I’m so sorry! I know that’s so stressful. How long since she stopped eating normally? It’s good you gave her simethicone and it’s great that she’s eating a bit! Avoid sugary stuff if possible, but treats like willow leaves, dried flowers, yummier hays, etc can be nice to tempt her. Some bunnies respond well to herbs like parsley or mint, too.
I know it’s so scary and that all-caps warning about this being an emergency has haunted me for the past 10 years that I’ve had bunnies. But in practice, as long as you’re getting something into them, in my experience they are a bit tougher than that and I don’t think you have to worry that she’ll be gone in the morning.
I’m no expert, so I defer to anyone more experienced. But fwiw, if I were you, right now I would keep tempting her with non-sugary treats, herbs, anything else. Sometimes if you put it right in front of them they’re a bit more likely to nibble. Then if by bedtime she’s still not eating much, I’d give her some more simethicone and some Critical Care. Also encourage her to drink more, if possible, and/or make a very watery version of Critical Care and give her that as well. (Or if you have subcutaneous fluids around, you could do that.) If you can keep her hydrated, and eating as much as possible, that’s your best bet. If she’s not doing better tomorrow morning, visiting a bunny-savvy vet would be something to consider.
Good luck and keep us posted!