Yes, I agree with playfelt. I would give her a bottle/snack and put her down in a playpen, maybe even in a main room until everyone else arrives or your kids get up. It's very possible that she might be tired or hungry. I know I am a ROYAL B myself if either of things are going on w me, and I am a full grown woman! LOL
Do you know what time she is going to bed at night? Good luck. This sounds awful!