late nights

As expected, my baby would keep me up until 5am most nights when she first came home. Then eventually it was only a few times a week, and finally she would usually make it by 3am. By the time she was 2 months she was going to bed by 1am. Now for that she is almost 3months old she wants to stay up until 5am again. I don't know why. I wonder if it is because school just started for her dad and so the only time she sees him is nights and weekends so she wants to stay up and play with him. The only thing is, he will go to bed and she will still be wide awake. Sure, she'll doze off a little, but as soon as I put her in her crib she is wide awake again. She sleeps all day too, no matter what I do. I hope she stops doing this soon. It will make my life much easier. If only I knew better ways to keep her awake during the day, but when she keeps me up all night I don't have the energy to stay awake during the day either.