L.A.
What has changed?
Her nap, she is only getting 1 nap?
How much out door playtime?
When do you all get home form work daycare, Or are you a SAHM? What timed does dad get home? Any of that change?
New baby?
Think about any changes.
If none,
Is she feeling ok?
Have you noticed more teeth coming or her molars?
Are her diapers a little runny?
Is she eating well?
Could be her nap needs to be moved to earlier in the day.. never past 2:30 pm and only for an hour and a half.
Make sure she gets to run and play and jump for an hour to an hour and a half in the morning AND again in the afternoon. Running errands does not count.
Make sure the evenings are not "tickle parties and chasing and teasing" around the house. They ened to be slower and calmer and quieter.
No TV./videos.
It takes a child double the time to calm down as it did to tile them up.
Hope this helps.