These are my standard answers to this after determining no fever and they don't look green, pale or sweaty:
"And....?"
"What would you like me to do about that?"
"What are you looking for?"
"I can't send home every kid that says they feel like they are going to puke. There would be no one left in school."
I'm bored with these answers and looking to shake it up a bit.
What do you say when not-really-sick kids tell you they feel like they are going to puke?