likely she feels insecured. you may want to talk to her at home, constantly, that you will come to pick her up at the end of the day. and very importantly, when you drop her off in the morning, do not linger, or hug her or show her that you feel sorry that you are leaving her there. she can sense it clearly, that you are sorry. you drop her off, say bye - you must say bye to her properly - then turn and go. not a fraction of eye lingering. hopefully saying bye to her properly in the morning and coming to pick her up later in the day will help her to make a clear connection that she is to be picked up by you at the end. do this yourself for a couple months, not by her father, since she shows him no trust.
when my daughter first went to daycare, i was told by the teacher that she might cry for sometime. she ended up crying for 4 hours the first day, 2hrs the next day, half hour on the third and the fourth day, she was fine.
another possibility is that you cuddle her or serve her whim too much at home, and she is not getting the same treatment at daycare. so she's not used to it and frustrated or even scared. you may try to treat her the similar way the daycare does. communicate with the daycare and see if you can identify any points you need to adjust you treatment of your daughter. it's only good for her in the long run you know.
good luck.
