What Is The Cause And Treatment For Depression?

Hi, just a question about grieving. I lost my mum whom I was very close with a month ago. I am married and have a daughter but feel like I cant grieve with my husband around. I cant let go. I am always conscious and don t want to just let it all out when he is around. I find myself quietly sobbing in the shower or late at night when it affects no one. Its very hard. I know im pushing people away. But I just need to be alone. Is this common?