As a cat lover, I can imagine how you're feeling. I googled "dehydrated kitten" and there is quite a bit of suggestions out there.
Have you tried just calling a vet? Explain your situation and I imagine they would be able to tell you some things that may help.
I'll be thinking of you. I need to go find my cat, wherever he' sleeping, and give him so loving right about now.
Good luck Hon and God Bless You for caring for this kitten,
Judy