To me, I just think she's very annoyed with you bothering her. My girl, Cerce, has made some very grumpy noises at me along with the head thing when I'm bothering her and she wants none of it. Maybe just let her be for a little while, let her stress level come down.
It may have something to do with her clutch but that's beyond my knowledge.
"Ladies and Gentlemen, hobos and tramps, cock-eyed mosquitoes, and bowlegged ants; I come here before you to stand here behind you and tell you something I know nothing about...."