urgent help

I have an old female boss, age 55 plus and divorced long time ago, still single no kids per she saying.
Trouble start last week.
Long story short, today we had guy off and he put me as backup in the email, I just found out today when someone ask me to do his work and I covered,
After I left office today, she called my cell around 5:30 pm and said I need cover something else for this guy, bad thing is I did not take laptop with me, I told her and she is mad, said tomorrow will have meeting with me to discuss.
For me, how should handle it tomorrow? if I think she is not fair, should I talk to her boss?

Thanks a lot, sorry for not been able to type Chinese