As soon as a child throws up I call the parents to come pick up. I can't take a child that cries until they throw up.

It very well may be teething, lack of sleep, colds, needles... the fact of the matter is... if you can't work with the child and it's taking a toll on you and the other child then regardless of what is causing it, maybe the child is no longer a good fit for your care.

645 is an extremely early start for a little one I think. She needs a morning nap. Could you force her down at 8:30 - 9 so it doesn't interrupt your day?

I would give notice to the parents that if it continues more then 2 weeks (or whatever you think you can take) then you will not be able to care for the child. It's not in the childs best interest to be in care throwing up, not eating and crying all day. I can't imagine that's what they want for their child.

If you choose to keep the child I would spend time re training to sleep. Stay in the room, maybe in a dark room on the main floor continuing to put down until she gets it again.

Good luck, I hate this part of the job.