Hi. I know this is late, and I hope you have already solved your problem, but if not, here is another way of looking at it:
How do YOU feel in the morning? I noticed that if I am crabby or frazzled in the morning, my son (3 yrs old) picks up on it and also becomes crabby and then we both just feed on each others' bad moods and it escalates.
Since your daughter wakes up fine near the same time other days, and you said bedtime is getting frustrating on before-daycare nights, I'm guessing she might be feeding off your frustration now even if it didn't start out that way.
If this is the case, see what you can do to make mornings (and bedtimes) easier for YOU. If you can have everything you need for the morning ready before you go to bed, then the morning won't feel as hectic. If you are more relaxed and less frantic to get out the door, maybe your daughter won't fight you as much.