N.P.
it actually sounds like either teething (two year molars and eye teeth both erupt at that time) or night terrors or over tiredness.
Lots of kids that age go back to needing two naps, or one REALLY long nap and 12 hours of sleep at night. She should be getting 15 hours of sleep in a day still. By the time she is 3 it will drop down to 14 hours of sleep needed. I have seen total transformations in behavior when an over tired child finally gets the sleep they need and I truely believe (after knowing and caring for LOTS of kids in my life) that sleep is the key to so many aspects of a child - health, intelligence, behavior, social skills.
What I would do is give her some motrin (well, generic cause of the recall) before naps and bed to makes sure teething pain is not bothering her. I would make her bedtime earlier (7 pm is a perfect bedtime for kids) and make sure she is getting a long nap of at least 2 hours every day.
Although it may be somewhat emotional I seriously doubt it. Kids that age adapt really quickly to new social arrangements as long as the rest of their life is constant and they get the sleep they need. And the reality is, that part of her life is what it is, it can not and will not change. You are going to have to make due with the new reality for her. She will survive and you will to, because you have to.
I promise and would bet money that if you increase her sleep she will be back to normal and it will have NOTHING to do with Daddy being in or out of the picture.