To cry or not to cry, That is the question.......

What do you do when all you want to do is lay in bed and cry? How do i go on knowing that the girls are not going to be happy? I feel like I have hit rock bottom and know longer have ways to get out. Dan is doing all he can to help but there seems to be no way out. My ex has his parents helping him and we just have use. I don't know what I'll do if I lose the girls. They are my world. I'm trying to be happy for them and let them think that everything is going to be ok, but I'm so worried its not. What I don't understand is why now. Why does he want them now and not when they were growing up. He didnt want his son so why them. I'm so lost right now and have no way of finding my way back. My depression is get worse and I don't know what to do. Someone please help me.