I would go with your gut on this OP.
Since she fired her previous Nanny for not putting the toys in their correct places, I have the feeling she you may be next on the chopping block due to the way she is acting.
I
totally agree w/you that she should talk to you if there is an issue so you can fix it vs. just shrugging it off and giving you the silent treatment. Perhaps she isn't the confrontational type. <---- Not giving her a
free pass by the way.
I wouldn't count on this job much longer.
It's only a matter of time, I think before she lets you go....