N.J.
Sounds like she is beginning to understand that she lost her daddy and maybe that means she could lose her mom too. Also there is always a bit of anxiety about getting left in day care no matter how nurturing and loving it may be.
It also sounds as though you care about this little daughter of yours, and maybe want to work out with her mother ways to be more involved in her life and assure her that you are not "lost" forever but will always be a part of her life because you are her father. Best of luck in working things out and helping your daughter to feel safe and confident!!
Blessings on you and your loved ones.
Great grandma N.