What the hell happened to my three year old?

I know the time change due to Daylight Savings can be a pain in the ass.  But can it cause my three year old to morph into a totally different kid?  The last two mornings she has woken up in the pissiest moods.  In fact, this morning, she walked out of her room, realized that I was making her lunch for school, yelled downstairs that she wasn't going to school, stomped back into her room and shut the door.  What the what??  Homey don't play that. 

When she finally did come downstairs, she was just mean to her sister.  There was a lot of "Don't look at me"s and a few "Go away, I don't want to play with you"s thrown around.  Ugh, if she's like this at three, Lord knows how's she'll be in her pre-teen and teen years. 

Thankfully, I did get her off to school.  I figured once she got there she would have a good time.  However, when I picked her up, her teacher informed me that she started crying after lunch and said "My Mommy isn't coming back."  Gah! That just kills me.  Of course, mommy always comes back. 

I really hope she's just out of whack because of the time change.  Because otherwise, I have no idea what is going on with her.