How scary

So glad your little one seems better now. Leaving her food down all the time does not mean that she's eating enough, though. I almost lost my Luna in the same way and she had food down all the time. She just wasn't eating enough of it. I had to start feeding her every two hours, around the clock, for a few weeks until she started eating better.
At her size, she needs to eat small frequent meals. Entice her with a little canned food mixed with her kibble and monitor how much she's eating. A dab of nutrical or similar stuff should help her appetite